the implications of global warming of 1.5ºc and 2ºc...the implications of global warming of 1.5 º...

The implications of global warming of

1.5ºC and 2ºC

Professor Sir Robert T. Watson FRS Professor Corinne Le Quéré FRS May 2018

Tyndall Centre for Climate Change Research Working Paper 164

The implications of global warming of 1.5ºC and 2ºC

Summary Report

Robert T. Watson - University of East Anglia

Corinne Le Quéré - University of East Anglia [email protected]

Tyndall Working Paper 164, May 2018

Please note that Tyndall working papers are "work in progress". Whilst they are

commented on by Tyndall researchers, they have not been subject to a full peer review.

The accuracy of this work and the conclusions reached are the responsibility of the

author(s) alone and not the Tyndall Centre.

The implications of global warming of 1.5ºC and 2ºC

Summary Report

Authors: Robert T. Watson and Corinne Le Quéré

Tyndall Centre for Climate Change Research, University of East Anglia

This summary report is based on research examining the implications of global warming of 1.5°C and

2°C project funded by (1) the UK department for Business, Energy and Industrial Strategy (BEIS) and

conducted by researchers at the Tyndall Centre and collaborators, and by (2) the Natural Environment

Research Council (NERC) and conducted by researchers at various universities. This summary is not a

critical assessment of these papers compared to others in the literature. Contributors listed in the

Appendix are gratefully acknowledged for their input.

This report contains research material that is not yet published and may be under embargo. Therefore

please do not share the report, and direct any requests to Asher Minns at the Tyndall Centre at

[email protected] .

May 2018

Final Report on the implications of global warming of 1.5ºC and 2ºC

Internal report only, please direct requests to [email protected]

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Outline

Introduction

Executive Summary

Part I: Context

• Historical and current emissions of greenhouse gases (GHGs)

• Implications of the Paris agreement pledges

• Fifth IPCC Report

Part II: Answers to Questions (combinations of questions requested by BEIS)

A: What are the implications of different interpretations of the 1.5ºC goal for impacts and emissions

pathways, and what global and regional rates of decarbonization are needed and when would net zero

emissions need to be reached to limit temperature rise to 1.5ºC compared to 2.0ºC. What are the key

assumptions?

B: What are the global and regional opportunities, challenges and risks of different mitigation strategies

and technologies to limit temperature rise to 2°C and 1.5°C? What major technological developments

are required and feasible are they, and what are the major technological uncertainties?

C: What are the societal and behavioural changes required to achieve these transformations and

their challenges?

D: What are the differences in the global and regional impacts and risks on human-related systems

between global warming of 1.5ºC and 2ºC, from both the resulting climate change and the

pathways needed to limit temperature rise? And are there any other benefits other than avoided

impacts? What are the uncertainties surrounding estimates of the impacts and how well can we

distinguish between the impacts at 1.5°C and 2°C?

Introduction

BEIS requested that the research and this report address a series of questions (listed in Annex1). Many of

the questions are over-lapping and have been integrated into those listed in the outline above, and one or

two of them cannot be answered as the research did not encompass the issues addressed in the questions,

e.g., the economic costs of stabilizing at 1.5°C and 2°C.



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Executive Summary

Context

• Global carbon emissions from fossil fuel burning, which reached an all-time high in 2017 after being

nearly constant during 2014-2016, need to peak imminently and decline rapidly to have any

possibility of achieving the Paris commitment of limiting warming to well below 2ºC;

• The current pledges under the Paris agreement are insufficient to limit global mean temperature

increases relative to pre-industrial levels to well below 2ºC. Instead global mean surface temperatures

will probably increase by around 3ºC, or more, and 1.5ºC will likely be exceeded in the decade of the

2030s and 2ºC in the 2060s;

• Global emissions from CO2 and other GHGs need to decrease to approximately zero to stop warming

at any level. Zero emissions from energy use can be achieved in principle, but because of expected

residual emissions of CO2 from some sectors (e.g. aviation, some industry), from non-energy use,

from other GHGs related to agricultural processes, removal of CO2 from the atmosphere (here called ‘negative emissions1’), e.g. through reforestation or Biomass Energy with Carbon Capture and

Storage (BECCS), will be necessary to stabilize any temperature rise.

Cumulative Carbon Emissions

• The cumulative CO2 emissions allowed post 2017 to achieve the 1.5ºC and 2ºC goals, because these

temperature goals are so near in the future, are dominated by uncertainties, ranging from about 100 to

800 GtCO2, and about 800 to 1700 GtCO2, respectively. These results are mostly higher than those

reported in 5th Assessment report of the IPCC2, but they include a limited number of studies only. The

IPCC special report on 1.5ºC to be published in October 2018 will provide an updated assessment.

• Estimates of the allowable amounts of cumulative carbon to achieve climate goals are dependent

upon: the probability (e.g., 50% versus 66%) of limiting climate change below a specified

temperature; the future evolution of non-CO2 emissions (especially methane and aerosols); the

magnitude of the carbon feedbacks through carbon released from natural wetlands and permafrost

thaw; the uptake of CO2 by the oceans; and the details of the calculations regarding the level of

present-day warming.

Peak emissions and rates of emissions reductions

• Rates of CO2 emissions reductions needed to meet the Paris climate commitments are stringent in all

reported publications, but the exact amplitude varies because the rate is highly dependent on: (i) the

cumulative CO2 emissions allowed; (ii) whether the model assumes an overshoot of the temperature

goal followed by negative emissions to bring temperatures back down; and (iii) whether the model

assumes emissions reductions start immediately or whether the emissions follow the NDCs3 until

2030.

• Similarly, it is urgent that global emissions peak soon to meet any scenarios consistent with the Paris

temperature goals. The vast majority of published scenarios that meet the 1.5ºC goal have peak emissions in the coming decade, even when considering overshoot followed by large-scale negative

emissions. All scenarios have a trade-off between the time of peak emissions and the amount of

BECCS deployed, whereby an earlier peak reduces the need for BECCS and other negative emissions

technologies and vice versa.

1 Negative emission technologies are also used in model projections to offset emissions at any level. 2 IPCC 5th Assessment Synthesis Report http://www.ipcc.ch/report/ar5/syr/ 3 The Nationally Determined Contributions (NDCs) are the pledges submitted to the UNFCCC under the Paris Agreement. Their mitigation goals mostly refer to year 2030.



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• Scenarios using the IMAGE integrated assessment model project annual rates of change in global

CO2 emissions in the 2020s of around -4.0%, and -2.5%, to achieve the 1.5ºC and 2ºC goals with a

66% probability respectively, assuming CCS is deployed at scale from 2020 and BECCS from 2030.

Excluding BECCS and other negative emissions technologies, the emission reduction rate for the 2ºC

goal was found to be slightly above 3% in the 2020s. Faster required rates of -5.4% and -2.7% to

achieve the 1.5ºC and 2ºC goals, respectively, were found using a simpler model with no CCS. As

these rates are global, faster rates need to occur in industrial countries to offset some growth

associated with development elsewhere.

• In the past decade, eighteen countries including the UK have decreased their emissions, largely due to

reduced energy demand (including energy efficiency) and deployment of renewable energy

technologies, but the average rates of -2.6% per year still fall short of the rapid rates needed to

achieve the Paris temperature goals.

The date to reach net zero emissions4

• The factors that influence the rates of emissions reductions also influence the date to reach net zero

emissions.

• Net zero global CO2 emissions were reached around 2050 and 2075 respectively, in the IMAGE

scenarios that achieve the 1.5ºC and 2ºC goals with a 66% probability, allowing for overshoot and use

of BECCS. A separate analysis with emissions following the NDCs until 2030 found comparable

results, with requirements to reach net zero around 2045 and in the 2080s for the 1.5ºC and 2ºC goals,

respectively. Note that the date to reach net zero for all greenhouse gases was not analysed here.

• If BECCS and other negative emissions technologies prove not to be technically, environmentally,

socially or economically viable at the scales assumed in the models, with only reforestation and

afforestation removing carbon from the atmosphere, emissions need to decrease to levels near zero

more rapidly, although small levels of above-zero emissions can remain during the full century.

• The date for the UK to reach net zero CO2 emissions was examined in one study using a simple

model initialised from current emissions. When assuming the global cumulative emissions are shared

based on equal per-capita emissions and BECCS is deployed at scale in the UK, but not including

equity measures for past responsibility, the year of net zero in the UK was similar to or slightly earlier

than that for the world. This result is particularly sensitive to a range of choices, including to various

measures of equity, and needs to be examined further.

Biomass energy with carbon capture and storage (BECCS)

• Most projections that keep warming below 2ºC rely heavily on the use of BECCS at large-scale to

produce negative emissions.

• However, there are critical uncertainties associated with the technical, economic and environmental

feasibility of BECCS. For example:

o this technique has not been demonstrated at the scale required and has received to date little

financial and political support;

o the required rate of deployment is extremely ambitious in many scenarios, exceeding in places the

historical rates for market uptake of fossil, renewable and nuclear technologies, and is entirely

dependent on incentives;

4 The term ‘net’ zero emissions refers to the sum of positive emissions plus removals. It can thus be achieved by reducing positive emissions to zero, or offsetting positive emissions by the active removal of GHG from the atmosphere.



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o its environmental and ecological sustainability, and therefore effectiveness, is questioned, in part

because two-thirds of the bioenergy crops are projected to be grown in regions with weaker

sustainability governance; and

o if BECCS involves replacing high-carbon content systems (e.g. boreal forests) with crops, then

afforestation and avoided deforestation are often more efficient for atmospheric CO2 removal

than BECCS.

• The significant issues raised on the plausibility of large-scale deployment of BECCS need to be

urgently addressed through a combination of finance, deployment, and research. Governments should

be very cautious on relying on this technology to meet the Paris commitments until large scale

deployment is set in motion. In the meantime, increased emphasis on an immediate and rapid

transition to a low-carbon economy is needed, in both the production and use of energy, as well as

aggressive mitigation of all sources of CO2 and other GHG emissions from all sectors.

Mitigation technologies and options

• Within most models, energy demand is poorly characterized compared with energy supply.

Consequently, highly ambitious decarbonisation of energy supply is considered in detail, whilst

opportunities for more aggressive reductions in energy demand are seldom included in future

projections therefore providing additional mitigation opportunities than are currently captured.

• While the energy transformations to achieve zero emissions are possible in some sectors (e.g.

buildings), zero emissions are currently thought to be unobtainable with foreseeable technologies in a

small number of critical sectors, including shipping, aviation and some industrial activities (e.g.

production of chemicals).

• In the IMAGE model, most mitigation in the critical sectors occurs through improvements in CO2

intensities, followed by energy intensities, but with a minimal use of reduction in energy demand. The

potential to reduce emissions varies widely by sector. For example, in the IMAGE model:

o Shipping and aviation: Limited decarbonization for shipping (half current emissions by 2100)

and aviation (no reductions by 2100) are achieved through a combination of fuel switching and

energy efficiency improvements, but emissions could also be reduced through slow steaming (for

shipping) and mode shift (for aviation) and some reduction in demand;

o Road transport: Rapid reductions in road transport emissions of up to 6% per year are achieved

through a combination of fuel switching, new technology vehicles, new low-carbon electricity

supplies and highly efficient vehicles, but additional mitigation could come from synthetic low-

carbon liquid fuels, modal shifts for passengers, smart road/cars, shifting freight to rail, and

demand management;

o Industry: Reductions in industry emissions of up to 4.5% per year are achieved mainly through

deploying industrial CCS in this relatively energy efficient sector, with additional mitigation

potential requiring a re-design of industrial processes to achieve a more efficient use of resources

and reductions in service demand through material efficiency and the circular economy.

Alternative options could include further electrification and fuel switch and increasing material efficiency.

• Achieving transformations in energy systems will require societal and behavioural changes, with the

following overarching issues and opportunities being identified globally:

o Given public opposition to certain low-carbon strategies (e.g. reduced indoor heating), it is critical

to increase public participation (e.g. via deliberative focus groups) in mitigation policy-making

and implementation, capitalizing upon public support for sustainable energy sources and

efficiency measures;

o Renewables are preferred as sources of energy, with nuclear and fossil fuels garnering the least support. Opposition to large-scale energy infrastructure often stems from perceived risks and poor

community engagement. Householder adoption of solar PVs is driven primarily by financial



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considerations as well as a desire to be environmentally-friendly. Biomass energy is

comparatively under-researched, with most concerns related to sustainability. There is low public

awareness of Carbon Capture and Storage (CCS), with mixed views about its benefits and risks

amongst those who do know about it.

o In principle the public are positive about energy efficiency measures, but barriers exist to the

adoption of measures (e.g. initial cost, habit). Demand-side reduction through restrictions on

energy services are often resisted by individuals. Overall, there is more public support for ‘pull

measures’, e.g., public transport, than ‘push measures’, e.g., increased taxes/tolls which may

restrict individual freedom. Behaviour change interventions have achieved energy savings of 5-

10%.

o There is potential to reduce emissions through disruptive innovations offering goods and services

with novel attributes to consumers, e.g., car-sharing, mobility-as-a-service, electric vehicle

integration with electricity grids, internet-enabled appliances, digitally-enabled food waste

reduction schemes, modular urban farming and smart infrastructure. These reductions are not

typically included in model projections. Scaling up evidence from early-adopter groups to the UK

population as a whole suggests additional emission reduction potentials of up to about 10% across

food, mobility and buildings.

Policies

• According to results based on the E3ME macro-economic model, policy measures needed to limit

warming to 1.5ºC are largely based on scaling-up existing and proposed measures, bringing forward

time scales of implementation and coordinated global actions, and tackling all sectors of the

economy. This includes ambitious levels of action through taxes, subsidies, efficiency incentives and

direct regulations. While substantial near-term green growth GDP and total employment gains are

possible in fossil fuel importing countries, in exporting countries there are generally negative impacts

on GDP and employment. Non-action and delayed action by individual countries and groups of

countries have a negative economic effect in the near-term on the country avoiding action, because of

increased dependence on energy imports, stranding of fossil-fuel assets and missing the benefits of

investment in low-carbon technologies.

Impacts and risks on human-related and ecological systems

• For most sectors and ecological systems, the impacts of climate change are reduced significantly by

reducing warming from 3.7ºC to 2ºC, and the impacts are statistically lower at 1.5ºC than at 2ºC.

• Losses in 2100 relative to the observed 1961-1990 climate for temperature changes of 3.7ºC5, 2ºC and

1.5ºC are projected to be (i) 13%, 5.1% and 3.7%, for crop yields; (ii) 550, 69, and 54 trillion $ for

net present value (NPV); (iii) 310, 61, and 30 millions of people affected by 100-year fluvial flooding

events; and (iv) 190, 87, and 64 millions of people at risk from drought in any given month;

• Considering climate change alone, limiting global warming to 1.5ºC above pre-industrial levels

avoids half the risks associated with warming of 2ºC for plants, animals, and insects in terms of

climate change induced range loss, and areas which benefit the most in terms of avoiding declines in

species richness are Southern Africa, Southern Europe and Australia.

• Temperature overshoot can have significant negative effects on ecosystems if they persist long

enough that rapidly-dispersing species can over-adapt to new conditions, and then need to retreat.

Temperature changes are projected to lead to extreme risks to population health affecting the ability

to perform essential activities of daily living such as physical work, across many tropical and sub-

tropical regions in response to future global warming of 1.5°C, and become widespread in these

5 A reference scenario with no climate policy beyond the Cancun pledges.



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regions around global warming of 2.5°C to 3°C. The exact population exposed depends on the

specific choice of thresholds, but conservative estimates are in the tens of millions, while top-end

estimates are in the billions of people.

• Projected changes in sea level in the 1.5ºC and 2ºC scenarios are lower in 2100 by 20-30 cm, and

substantially lower in 2300 by 2-3m compared to a scenario that exceeds 4ºC. Even under climate

stabilization, sea level rise continues over multiple centuries. Millions of people are projected to be

displaced under all scenarios without additional adaptation measures.

• Projected levels of ocean acidification for the 1.5ºC and 2ºC scenarios in 2100 are of about 10% and

30% higher acidity respectively, compared to the average level between 1986 and 2005. These levels

mean waters become increasingly corrosive to carbonate shells, with the worst effects to occur in

winter at high latitudes of both poles. Global mean ocean acidification stabilizes within a century

under both scenarios.



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Part I: Context

Historical and current emissions of greenhouse gases

Despite overwhelming scientific evidence that increased atmospheric concentrations of greenhouse gases

cause human-induced climate change, with predominantly adverse effects on socio-economic sectors,

human health and ecosystems, climate action has been delayed and global GHG emissions have continued

to increase steadily from 38GtCO2-eq in 1990 to about 54GtCO2-eq in 2017. In spite of the Paris

agreement, fossil fuel CO2 emissions in 2017 reached an all-time high, following three years of nearly no

growth. This increase illustrates the challenge of meeting the Paris agreement.

Implications of the Paris agreement pledges

As part of the Paris Agreement, 162 pledges were submitted to the UN Climate Change Convention

describing how each country intends to tackle climate change. These pledges cover 189 countries

accounting for 98% of global GHG emissions6. The Paris Agreement indicates a commitment by

countries to combat climate change by limiting global mean temperature increase well below 2ºC by 2100

relative to pre-industrial levels, and pursuing efforts to limit warming to 1.5ºC. However, the current

pledges must be implemented and strengthened as soon as possible.

To keep warming well below 2ºC, global GHG emissions should be reduced by about 20-25% in 2030

compared to now, according to the UNEP gap report7, assuming continued deep decarbonisation and

significant uptake of CCS and BECCS afterwards. Without the Paris Agreement pledges, emissions are

projected to increase by about 20%. If the unconditional pledges are implemented, global GHG emissions

are expected to increase by about 6% in 2030, while they would remain about the same with the further

implementation of the conditional pledges.

The current pledges under the Paris agreement therefore fall far short of what is necessary to limit global

warming to well below 2ºC. With current pledges and assuming CCS and BECCS deliver, warming of

around 3ºC is projected. With a total failure of the Paris Agreement, warming would be higher at around

4ºC, according to the UNEP gap report. Without an urgent and significant strengthening of the pledges,

1.5ºC will likely be the mean temperature rise in the decade of the 2030s and 2ºC in the 2060s.

Fifth IPCC Report

The last report by the IPCC was published in 2013-2014 (called IPCC AR5). It established the scientific

and technical basis associated with limiting warming to less than 2°C compared to pre-industrial levels

(taken as 1861-1880) with a probability of >50%, and >66%, but included relatively little detail on these

scenarios. IPCC AR5 made clear that in order to limit climate change at any level, a fixed cumulative

budget of CO2 could be emitted, and it provided this cumulative budget for various temperature goals.

This budget and the uncertainties around it are discussed in detail below. Following the Paris Agreement,

6 President Trump has since announced that the US plans to withdraw from the Paris Agreement. 7 According to Rogelj et al. (2016; https://www.nature.com/articles/nature18307), global GHG emissions would

increase from current levels of 54 GtCO2-eq to: (1) 65 (range 60-70) GtCO2-eq in 2030 without the Paris Agreement

(+20%), (2) 55 (52-58) GtCO2-eq with unconditional pledges only (+6%), and (3) about current level at 54 (52-54)

GtCO2-eq with both conditional and unconditional pledges. The difference between the projected level of global

GHG emissions in 2030 with full delivery of all Paris Agreement pledges, and what is needed to stay well below

2ºC, i.e., the emissions gap, is 11 to 13.5 GtCO2-eq according to the UN Gap Report 2017, or 33% above the 2ºC

pathway (assuming CCS and BECCS work and are implemented at a global scale).



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the UNFCCC requested an analysis of the 1.5ºC goal from the IPCC. The IPCC report is expected

October 2018.

Part II: Answers to Questions

A) What are the implications of different interpretations of the 1.5ºC goal for impacts and emissions

pathways, and what global and regional rates of decarbonization are needed and when would net

zero emissions need to be reached to limit temperature rise to 1.5ºC compared to 2ºC. What are the

key assumptions?8

Emissions pathways consistent with different temperature commitments can vary depending on a number

of key issues discussed in this section. The key issues include the allowable cumulative greenhouse gas

emissions to achieve stabilization at 1.5ºC and 2ºC and the magnitude of any acceptable overshoot (where the temperature goal is first exceeded and then returns back to a lower level). These issues are in turn

influenced primarily by the magnitude of the emissions of non-CO2 gases and by the feasibility of

delivering large-scale negative emissions. The chosen cumulative emissions and acceptable overshoots

then result in a given rate of decarbonisation and date by which net zero emissions are required, with the

options and opportunities discussed in Section B. The implications of the overshoot on key socio-

economic and ecological impacts are discussed in Section C.

Cumulative Carbon Emissions

Estimates of the allowable amounts of cumulative carbon emissions to achieve the 1.5ºC and 2ºC goals

are dependent upon the probability of achieving a specific goal (e.g., 50% versus 66%), the future

evolution of non-CO2 emissions (especially methane and aerosols), the magnitude of the carbon released

from natural wetlands and permafrost thaw, the uptake of CO2 by the oceans, and the details of the

calculations regarding the level of present-day warming. Because of the multiple choices, a broad range

of numbers has been published. The summary below includes the analysis done as part of this project,

compared to the numbers published by IPCC AR5.

IPCC AR5 reported cumulative emissions to climate goals from year 2010 with a probability of >50%,

and >66%, which we convert here to budgets starting from year 2017. Taking into account the emissions

from non-CO2 GHG, there are under 750 GtCO2 remaining for a >66% chance of 2°C, and 850 GtCO2 for

a 50% probability. The carbon budget falls to about 150 GtCO2 for a >66% chance of staying below

1.5°C, and 300 GtCO2 for a 50% probability (Table 1).

Combined uncertainties in cumulative budget approach: Table 1 shows a wide range of net cumulative

CO2 emissions allowed from 20179 from the different studies to achieve the 1.5ºC and 2ºC goals for 50%

and 66% probabilities (GtCO2), ranging from about 100 to 800 GtCO2 for the 1.5ºC limits, and about 800

to 1700 GtCO2 for the 2ºC limits. New results are mostly higher than those reported in IPCC AR5 based

on complex models, but they include a limited number of studies only. An IPCC special report on 1.5ºC

warming is expected October 2018 and will provide an updated assessment of cumulative emissions to

various temperature goals. The 1.5ºC goal in particular is so close in the future that the cumulative budget

approach for this goal is overwhelmed by uncertainties, although they are all extremely small (less than

about 20 years at current emissions levels).

8 A combination of questions 1 and the first part of 2. 9 All entries in the table have been converted to post-2017 emissions (from 01 January 2017) from those reported in

their papers.



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Table 1. Cumulative emissions of CO2 (GtCO2) allowed from 2017 to keep warming to various

commitment levels, from the most (left) to the least (right) stringent. The table includes values published

in the IPCC AR5 synthesis report, and the new studies detailed here. Numbers are rounded to nearest 10.

Study 1.5ºC (66%) 1.5ºC (50%) 2ºC (66%) 2ºC (50%)

IPCC AR510 150 300 750 850

van Vuuren11 110 770 1730

Goodwin12 720-750 790-830 1450-1510 1560-1620

Comyn-Platt13 530-720 1370-1730

Millar14 520-600 1220

Future Pathways based on the IMAGE Integrated Assessment Model: Van Vuuren et al. (2017)

considered a range of emission scenarios that achieve the Paris goals using the IMAGE model, which was

designed to explore emissions pathways consistent with the low end of climate change projections, and

has detailed representation of energy, particularly the supply side, and land use transformations. They

show that technology pathways still exist to reach the Paris agreement commitments of 1.5ºC and less

than 2ºC, but very stringent emission reductions will be needed, and like most model projections, the

model relies heavily on the use of BECCS at large-scale to produce ‘negative emissions’, later this

century. These pathways suggest that to stay below 1.5ºC requires emissions from 2017 to be about 110

GtCO2 (with 66% probability) and to stay below 2ºC requires emissions to be about 1730 and 770 for

50% and 66% probability, respectively (Table 1). The 1.5ºC goal is equivalent to only about one year of

current emissions, meaning that any further emissions would need to be offset by negative emissions in

the future and would create an overshoot in warming. The limitations of BECCS are discussed below.

Future Pathways based on theory and geological evidence: Goodwin et al (2018a) generated a large

ensemble of climate simulations consistent with both geological and historical observations of climate

change, and integrated these into the future to evaluate how much carbon can be emitted and still remain

under the 1.5ºC and 2.0ºC warming goals at different likelihoods. Their analysis suggests that to stay

below 1.5ºC requires emissions from 2017 to be about 730 GtCO2 and to stay below 2ºC requires

emissions to be about 1485 GtCO2, both for 66% probability and allowing no overshoot (Table 1).

Carbon Budget using the observational record: Millar et al. (2017a), using the historical observations

record to date, concluded that the remaining carbon budget for a 66% chance of achieving the 1.5°C goal

is likely to be significantly more than estimated by IPCC AR5. Using simple regression analysis between

cumulative CO2 emissions and global mean warming and assuming a 25% contribution of non-CO2

warming to peak warming gives an observationally derived best-estimate of the remaining 1.5°C carbon

budget of 880 GtCO2, or about 30 years of current emissions (Table 1; see also Millar et al. 2017b). The

study accounts for the uncertainty in historical non-CO2 radiative forcing using a standard detection and

attribution technique.

10 IPCC AR5 synthesis report Table 2.2, reported post 2010 values for cumulative carbon, using the period 1861-

1880 as reference year; these values are based on the complex models. 11 van Vuuren et al 2017 reported cumulative values from 2010 -2100, hence needed a major correction for post-

2017. 12 Goodwin et al 2018a reported post 2017 values for cumulative carbon. 13 Comyn-Platt et al 2018 reported post 2015 values for cumulative carbon with permafrost and methane feedbacks. 14 Millar et al 2017a reported post 2015 values for cumulative carbon – these values have also been corrected to fit

the observed temperature change since pre-industrial times, 1.01ºC rather than 0.93ºC.



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Effect of methane mitigation: Collins et al. (2018) modelled the impact of methane mitigation on the

cumulative CO2 budget. They found that reducing methane levels increased the equivalent of about 100

GtCO2 of allowable carbon emissions for every 100 ppb decrease in methane. For comparison, methane

concentrations have increased around 8 ppb per year in the past decade, therefore potential CH4

reductions still do not detract from urgent need to reduce CO2 emissions although they reduce the scale of

the mitigation needs. The most ambitious methane mitigation scenario (as captured by the difference

between a high and low CH4 scenario) was equivalent to an additional 862 GtCO2 by 2100 for the same

temperature goal, illustrating the importance of CH4 differences among scenarios for the cumulative

budgets assessments as shown in Table 1. They investigated both a monotonic increase to 1.5°C and an

overshoot returning to 1.5°C degrees. These did not differ greatly in terms of the allowable cumulative

carbon emissions, and the effects of methane mitigation were independent of the temperature pathway.

Methane mitigation also increased plant productivity and reduced air pollution with greater climate and

social benefits than assumed by IAMs, and hence identified a major deficiency/uncertainty in the

investigation of methane mitigation techniques and their costs.

Impact of permafrost thaw and natural methane emissions: Comyn-Platt et al. (2018) considered the

impact of permafrost thaw and natural methane emissions on the cumulative budgets, based on three

temperature profiles: two reaching 1.5°C by 2100 (a) asymptotically and (b) with an overshoot first to

1.75°C; and one profile reaching 2°C. The model results suggest that permafrost thaw and natural

methane feedbacks will reduce the total allowable anthropogenic CO2 emissions by about 200 GtCO2 up

to 2100 for both of the 1.5°C scenarios, and by 240 GtCO2 for the 2°C scenario, corresponding to a

reduction of approximately 4 and 5 years in emissions. Table 1 shows the corresponding post 2017

cumulative emissions.

Cumulative budget revision based on validation of oceanic CO2 uptake: Halloran et al. (2018) assessed

the oceanic uptake of atmospheric CO2 in the CMIP5 models underlying IPCC AR5, to assess the

reliability of given cumulative budgets. Where enough observational data exists for robust assessment,

CMIP5 models either overestimate or (within uncertainty) agree with observed trends in surface ocean

CO2 rise, implying that models underestimate ocean CO2 uptake trends. Assuming that this is not

cancelled by those areas where we can’t undertake robust comparisons, and that these trends continue (as

our results for the North Atlantic suggest), this implies that the CO2 emissions compatible with 1.5°C

degrees are higher than those provided by IPCC AR5. Therefore the budget may be higher because there

is greater capacity in the ocean sink than represented in the CMIP5 models.

Rates of emissions reductions

Rates of CO2 emissions reductions needed to meet the Paris climate commitments are stringent in all

reports, but the exact amplitude varies because the rate is highly dependent on: (i) the cumulative CO2

emissions allowed; (ii) whether the model assumes an overshoot of the goal followed by negative

emissions; and (iii) whether the model assumes emissions reductions start immediately or are delayed.

Scenarios using the IMAGE model project annual rates of change in global CO2 emissions in the 2020s of

about -4%, and -2.5%, to achieve the 1.5ºC and 2ºC goals with a 66% probability respectively, assuming

CCS is deployed at scale from 2020 and BECCS from 2030. Excluding BECCS and other negative

emissions technologies, the emission reduction rate for the 2ºC goal was found to be slightly above 3% in

the 2020s.

Goodwin et al. (2018a) reported faster required rates of -5.4% and -2.7%, using an idealized function with

no CCS (WASP Earth model), and assuming reductions started immediately. Faster rates of -4.5 % in the

2020s for the 1.5ºC goal were also reported by Comyn-Platt et al. (2018). For the 2ºC goal however, rates

of -3.8% are required if reduction begin in 2030 and -2.4% if they begin in 2020, probably reflecting

additional mitigation from methane in those scenarios.



12

As these rates are global for the 2020s, faster rates need to occur in industrial countries to offset some

growth associated with development elsewhere.

The date to reach net zero emissions

Global CO2 emissions need to decrease to approximately zero to stop warming at any level. The date to

reach zero emissions is highly dependent on: (i) the cumulative CO2 emissions allowed to meet the chosen

climate goal; (ii) whether the model assumes an overshoot of the goal followed by negative emissions;

and (iii) whether the model assumes emissions reductions start immediately or whether the emissions

follow the NDCs until 2030.

Net zero CO2 emissions were reached in 2050 and 2075 respectively, in the IMAGE scenarios that

achieve the 1.5ºC and 2ºC goals with a 66% probability, allowing for overshoot and BECCS (figure 2).

Net zero CO2 emissions are needed about 30 years later when the probability and goals are changed from 2ºC with 66% probability to 2ºC with 50% probability (or 1.5ºC with 50% probability to 2ºC with 50%

probability), or when they are changed from 1.5ºC with 66% probability to 2ºC with 66% probability.

Limited BECCS mean reductions in CO2 emissions need to happen faster and reach levels near zero

earlier, coupled with larger contributions from other GHGs.

Figure 1: Different 1.5ºC and 2ºC emission pathways, 2010 – 2100. The scenarios are: (i) default 3.4 (3.4

W/m2 in 2100) has a 50% probability of staying below 2ºC in 2100; (ii) default 2.6 (for 2.6 W/m2 in

2100) has a probability of at least 66% of staying below 2ºC in 2100; (iii) no BECCS 2.6 is similar to

default 2.6 but it minimizes the use of BECCS and policies are set in place earlier; (iv) default 2.0 has

66% probability of staying below 1.5ºC and has an overshoot of about 0.2ºC. Adapted from van Vuuren

et al. (2017).

Figure 1 shows that emissions go negative around 2050 (default 2.0) and 2075 (default 2.6) in the

IMAGE model, thus requiring negative emission technologies to achieve the goals. Negative emissions in



13

the below 1.5°C (default 1.9) and well below 2°C (default 2.6) scenarios shown in figure 1 amount to

about 750 and 200 GtCO2, respectively. However, it is important to recognize that there are biophysical

limits to carbon reduction techniques (afforestation, bioenergy and carbon storage), because of potential

undesirable effects on food security, biodiversity and risks related to CO2 emissions. But, to achieve the

1.5°C goal without overshoot would require CO2 emissions to decline to net zero around 2030-2035,

which is highly unlikely to be feasible, as is the potentially unrealistic levels of negative emissions (this

depends obviously on the uncertainty range for the carbon budget for 1.5ºC discussed earlier). Achieving

the 1.5°C goal, with or without BECCS, will be an extremely difficult challenge.

Similarly, Goodwin et. al. (2018b) concluded that assuming that the NDCs are followed to 2030, global

net emissions need to be restricted to net zero by year 2045 to achieve the 1.5ºC goal, with a possible

overshoot up to 1.7°C warming into the 2050s followed by net negative global emissions for the rest of

the century to bring warming back down to 1.5°C. For a 2.0°C goal, the best estimate for when global net

emissions must reach net zero is during the 2080s, with a range from as early as the late 2050s to the end

of the 21st century. The key assumptions for the timings are that non-CO2 emissions follow that

prescribed in RCP2.6.

When considering regional circumstances, it is expected that countries would reach net zero emissions in

different years depending on their current trajectories and the regional potential, capacity and willingness

to develop and deploy negative emissions technologies. Peters and Andrew (2018) developed a simplified

method to share the global mitigation burden among countries using two alternative assumptions, one

based on inertia/grandfathering and one on population. Under this simplified framework, the date for the

UK to reach net zero CO2 emissions is similar to or slightly earlier than the date to reach net zero

globally, when sharing cumulative emissions based on equal per-capita distribution and assuming BECCS

is deployed at scale in the UK. These results are similar to the 1.5ºC scenario of the IMAGE model for the

corresponding region (Western Europe), while in the 2.0°C IMAGE scenario, net zero is reached 10 years

earlier in Western Europe compared to the world. The factors influencing the year of net zero are complex

and intertwined, and include choices about burden sharing15, current emissions trajectories, the size of the

anticipated negative emissions, and the availability of local storage for CCS. As shown in Fig. 1, the year

of net zero is not necessarily a good indicator for the temperature goal, which can, in theory, be reached

without the need of achieving net zero emissions globally but by introducing more rapid mitigation

measures early on.

Challenges associated with Biomass Energy with Carbon Capture and Storage (BECCS)

BECCS is relied upon heavily in scenarios that limit global mean temperature increase to 1.5°C or 2°C as

a potential measure to offset residual emissions from the hard-to-decarbonise sectors, such as agriculture

and land-use change, aviation, shipping and industry (see below). BECCS also allows an overspend of

carbon budget so other sectors can decarbonize more slowly. Models tend to use large amounts of

BECCS assuming robust governance of bioenergy provision and significant policy support of CCS in the

near term, they emerge in models as cost-effective in a high carbon-tax world. However, there are critical

uncertainties associated with the technical, economic and environmental feasibility of BECCS. This

technique has not been demonstrated at the scale required and has received to date little financial and

political support. The specific issues to be addressed are described below.

BECCS in the IMAGE pathways: Vaughan et.al. (2018), analysed the key implicit and explicit

assumptions about BECCS in three low emission scenarios with the IMAGE model ranging from the

1.5ºC goal with 66% probability to the 2ºC goal with 50% probability. They concluded that:

15 See for example Robiou du Pont et al. (2017) https://www.nature.com/articles/nclimate3186



14

• CCS deployment rates are very challenging compared to historical rates of deployment of fossil,

renewable or nuclear technologies and are entirely dependent on stringent policy action to incentivise

CCS;

• Half of all global CO2 storage occurs in USA, Western Europe, China and India and the storage

required is compatible with recent regional storage estimates;

• Biomass residues account for about half the bioenergy used and have fewer sustainability concerns

than energy crops;

• In the model, energy crops cannot be grown on forest or food production land. However,

implementing this in the real world is dependent upon robust regulatory frameworks at a regional

level;

• Poor governance of the sustainability of bioenergy crop production can significantly limit the amount

of CO2 removed by BECCS, through soil carbon loss from direct and indirect land use change. Only one-third of the bioenergy crops were grown in regions with developed governance frameworks;

• Ensuring BECCS delivers CO2 removal will require the development of robust and joined-up

approach for monitoring BECCS and tracking progress.

Harper et.al. (2018) explored the land-climate-carbon cycle interactions in a new 1.5°C scenario

(produced by the IMAGE group) that includes afforestation/reforestation/avoided deforestation and

BECCS, to remove CO2 from the atmosphere. Harper et al. (2018) assume all biomass is from energy

crops. They concluded that BECCS could be far less efficient for carbon dioxide removal than often

assumed, and that as a result, BECCS is unlikely to deliver the substantial negative emissions required to

stabilize at 1.5°C without significant overshoot. Harper et al. (2018) also argue that carbon removal

though BECCS, which is assumed in most 1.5°C or 2°C scenarios, is uncertain because it strongly

depends on underlying assumptions with respect to yields, land-use change emissions, and efficiency of

CCS.

In the IMAGE 1.5°C scenario, in order to meet the stringent requirements to stabilize at 1.5°C without

significant overshoot, bioenergy crops are assumed to replace some natural forests at high latitudes. This

is consistent with assumptions within IMAGE of high-yield bioenergy crops and efficient CCS, and that

~75% of the initial aboveground biomass is used for BECCS. However, Harper et al. (2018) found that

soil carbon emissions following the deforestation overwhelmed the carbon gains from bioenergy crops –

significantly reducing the efficiency of BECCS. The loss of soil carbon in regions with high initial carbon

density makes it difficult for BECCS to result in a net negative emission of carbon dioxide. In considering

these ambitious climate goals, we therefore need to consider the net impact of the avoided climate change

and the impact of the additional mitigation efforts required, i.e., a major challenge is to stabilize the

climate well below 2°C, without mitigation options (such as BECCS) producing worse negative impacts

than the additional climate change that they are designed to avoid.

BECCS and natural ecosystems: Harper et al. (2018) argue that if BECCS involves replacing high-carbon

content systems (e.g. boreal forests) with crops, then afforestation and avoided deforestation (and

presumably reforestation and forest restoration) are often more efficient for atmospheric CO2 removal

than BECCS. Hence, the development and monitoring of strong governance for the sustainable provision

of bioenergy is critical.

The significant issues raised on the plausibility of large-scale deployment of BECCS need to be urgently

addressed through a combination of finance, deployment, and research. Both biomass energy and CCS are

in use at small scale now, but they have not been combined and their large-scale deployment is untested.

Therefore, resolving the finance issues and setting deployment in motion may be the most useful next

step, beyond the many research and developments that are needed to resolve existing and emerging

issues. The state of knowledge on BECCS is currently insufficient to warrant the widespread assumption

used in model scenarios that they will work at scale. Governments should be very cautious on relying on



15

this technology to meet the Paris commitments until large scale deployment is set in motion. In the

meantime, increased emphasis on a rapid transition to a low-carbon economy is needed, in both the

production and use of energy, as well as aggressive mitigation of all sources of CO2 and other GHG

emissions from all sectors.

B) What are the global and regional opportunities, challenges and risks of different mitigation strategies

and technologies to limit temperature rise to 2°C and 1.5°C? What major technological developments are required and how feasible are they, and what are the major technological

uncertainties?

Recent decarbonisation rates

Observed underlying drivers of decarbonisation in 18 countries: Le Quéré et al. (2018) examined the

emissions drivers over the decade 2005-2014 in 18 countries where emissions decreased the fastest16, representing 28% of the emissions. The median decrease in emissions was -2.6% per year (range of -4.6

to -0.9%). These countries are decreasing their carbon intensity (about -3.4% per year) faster than other

countries with higher GDP growth rates (typically much less than 2% per year). Among this group of

countries, decarbonisation was achieved through a decrease in energy demand, and an increase in the

deployment of renewable energy displacing fossil fuels. A distinct correlation was observed between the

number of energy and climate policies in place and the rate of decarbonisation. In principle there is no

inherent reason why these sustained decarbonisation changes in energy systems are specific to the

countries examined, thus, they could be expanded elsewhere.

Drivers of decarbonisation in models: The plasticity of energy demand coming out of the analysis of the

18 decarbonising countries appears to be larger than IAMs generally suggest. In their decarbonisation

scenarios, most IAMs project large increases in energy demand, matched by even larger deployment in

renewable energy and increased efficiency of fossil-based energy production (reductions of losses and/or

change of fuel type e.g. coal to gas). This behaviour is different from what is observed in the past decade

in the decarbonising countries, where demand has been the main trigger of emissions reductions, followed

by renewable energy deployment, with little change in the efficiency of fossil-based energy production.

The IMAGE model behaved more like the observations when it was used to produce low emissions

pathways, i.e., the 1.5ºC and 2ºC scenarios, compared to a baseline scenario of 3.7oC.

Therefore, the potential for near-term CO2 emissions reductions through changes in energy demand may

be underestimated in model projections. Further support for reductions in energy demand could tackle

consumption or efficiency of energy services and energy conversion in end-use technologies, with more

detailed representation of drivers of energy demand in models potentially helping to further explore the

solution-space for deep mitigation.

Sectoral analysis using the IMAGE model

Sharmina et.al. (2018) analysed the IMAGE model to show that most additional mitigation in critical

sectors occurs through improvements in CO2 intensities, followed by energy intensities, with minimal

reductions in service demand, except for aviation where growth in service demand in the 1.5ºC scenario is

half of that in the 2ºC scenario. This is high risk strategy. In contrast, a low risk strategy would mitigate

across all underlying drivers, i.e., service demand, energy intensity and CO2 intensity17,18.

16 Only countries where both the territorial and consumption emissions decreased were selected in this analysis.

International transport is not included. 17 Detailed analysis by sector is provided in the paper. 18 Decarbonisation rates for the 2020s by sector and region are available.



16

Aviation and shipping:

• In the IMAGE scenarios:

▪ In the long term, the IMAGE scenarios project limited decarbonisation potential in both aviation

and shipping. By 2100, shipping emissions are about half of the present-day level, while

aviation emissions are around 20-30% below the present-day level. These significant and

ongoing emissions are, in most models, assumed to be compensated by the large-scale

deployment of BECCS;

▪ In the short to medium term, the IMAGE scenarios project modest cuts to absolute emissions

from both sectors. From 2030-2050, reductions of 1-3% per year in aviation CO2 emissions take

place. Shipping CO2 is halved over a period of 20 to 70 years, depending on the stringency of a

scenario;

• Both sectors are truly international, and decarbonisation rates are unlikely to vary significantly by

region, except if different carbon taxes are applied;

• Emission reductions in the aviation and shipping sectors (including those represented in IMAGE)

could be achieved using a combination of fuel switching, energy efficiency improvements, slow

steaming (for shipping), mode shift (for aviation), and some reduction in demand. The key risks for

air- or seaborne transport are weight constraints and long distance between re-fuelling stations. For

example, alternative energy sources and emission reduction technologies, such as CCS, are not

readily available for aircraft, given the crucial role of weight in aircraft design. Emerging

technologies towards electric planes are at early stages of development and while they are unlikely to

be deployed at scale in time, they could contribute to some efficiency improvement beyond current

scenarios provided they do not lead to increased demand. Low availability of stations around the

world for ships and aircraft to refuel using new and renewable fuels is another major constraint.

• Benefits from technology and operations are mainly incremental, though not fully exploited at the

moment.

• Demand constraints are likely required in stringent mitigation scenarios but hold risks to economic

development, particularly for export-led economies and small island economies dependent on sea

transport.

• International policy in aviation and shipping is currently not aligned with emission reductions

required over the next few decades, starting in 2020, to achieve the 2°C goal, let alone 1.5°C.

Road transport:


▪ Global road transport emissions decrease to nearly zero in the 1.5°C scenario by 2050, and in

the 2°C scenario by 2100;

▪ In the highest emitting world regions (including the USA and Western Europe), road transport

emissions decrease by 2050 at around 6% per year in the 1.5°C scenario until they reach net

zero emissions, while the 2°C scenario projects lower reductions in the short term, followed by

strong reductions later in the century;

▪ In the fastest growing regions (including Brazil, China, India and Indonesia), road transport

emissions fall gradually by 2050 and at a very high rate (around 6% per year) after 2050 in the

1.5°C scenario, while in the 2°C scenario they increase by around 2.4% per year by 2050 in the

and then fall rapidly by 5.4% per year thereafter;

• Emission reductions could be achieved through a combination of fuel switching with new technology

vehicles (e.g. electric vehicles (EVs) using batteries charged with low-carbon electricity, fuel cell

vehicles running on hydrogen), synthetic low-carbon liquid fuels replacing fossil fuels in internal

combustion engine vehicles (ICEVs), highly efficient vehicles, modal shifts for passengers, smart

roads/cars, shifting freight from road to rail, and demand management. There are a several

uncertainties related specifically to new technology vehicles;



17

• One uncertainty is the reliability and practicality of fuel cell technologies. For example, fuel

contamination can affect the durability and stability of proton exchange membrane fuel cells. The

feasibility of upgrading the entire fuel distribution system for privately owned vehicles to support

hydrogen as an energy carrier is low in the short term. It may, however, be a solution for larger

vehicles such as trains and road freight vehicles;

• Another uncertainty is how much new low-carbon electricity will be available for plug-in vehicles

and for generating hydrogen (to be used in fuel cells or to create synthetic liquid fuels). Other sectors

will simultaneously need to shift to low-carbon electricity from fossil fuels, and grid output would

need to expand considerably to also power road transport. However, since EVs have better drivetrain

efficiency than ICEVs, less energy overall would be needed for electrified fleets;

• Another uncertainty is the rate at which the specific energy (energy per unit of mass), cost, reliability

and availability of large traction batteries for EVs can be improved to support acceleration of EV

production and market diffusion. The weight of batteries needed to provide the same range as ICEVs

reduces the overall efficiency of the vehicle, and so vehicles powered with liquid fuels are still better

all-round from a consumer point of view for some types of driving needs. Overall vehicle efficiency

improvements can ameliorate some of these issues. For freight, complete electrification is possible

but could require significant redesign of vehicles. Availability of rare metals needed for new

technologies (e.g. platinum for fuel cells, lithium for batteries) could slow down the expected growth.

• Finally, EVs can have higher embodied GHG emissions than ICEVs, and also possibly higher

lifecycle GHG emissions, depending on the GHG content of the electricity supply.

Industry:


▪ The average CO2 emission reduction rate in this sector between 2010 and 2050 is 4.4% per year

in the 1.5°C scenario and 1.2% per year in the 2°C scenario. During the second half of the

century, the emission reduction rates in the two scenarios are similar, at 4.1% and 4.5% per year

respectively;

▪ By 2100, industry’s global CO2 emissions in the 1.5°C scenario are around four times lower

than in the 2°C scenario;

▪ The largest regional cuts in CO2 emissions occur in the USA and Western Europe by 2050

(more than 7% per year) in the 1.5°C scenario;

▪ In the 2°C scenario, Brazil, India and Indonesia see modest growth in industry emissions in the

first half of the century, followed by relatively deep cuts of up to 6% per year between 2050 and

2100;

▪ Emission cuts are primarily achieved through reductions in CO2 intensity, through fuel

switching (most importantly to electricity) and potentially through deploying industrial CCS.

Energy efficiency improvements contribute to further emission reductions, although the

industrial sector is already highly energy efficient.

▪ There is limited representation of material efficiency and circular economy within IMAGE,

which primarily focuses on fuel switching and energy efficiency measures in industrial

processes, however, IMAGE does include some elements of material efficiency (e.g. recycled

scrap metal) and circular economy through lifestyle and economic variables, such as changes in

annual use of iron and steel (mn tonnes/yr) and changes in the mode of transport (billion

pkm/yr).

• Key challenges in decarbonising industry relate to the fact that the sector has had a long-standing

focus on energy efficiency as a cost-cutting measure and has all but exhausted the potential for further

emission reductions from efficiencies. Moreover, growing global demand for products and services is

leading to higher absolute emissions from production and manufacturing;



18

• Mitigation for 1.5°C, while avoiding heavy reliance on an already-stretched low-carbon power

supply, requires a re-design of industrial processes to achieve a more efficient use of resources, and

hence reductions in service demand, through material efficiency and the circular economy.

Policy options

Holden et al. (2018), Mercure et al. (2018), and Pollit et.al. (2018) investigated two principal policy

scenarios, finding that the 1.5°C goal could be met if it was interpreted as a 50% probability of not

exceeding the 1.5°C goal, with a strictly limited amount of negative emissions and without excessively

high carbon tax. But this was only possible with urgent action by all major emitters and using all the

policy levers available (tax, regulation, etc.). This was found to be equivalent to 94% probability of

remaining below 2°C. A scenario with slightly weaker action on all fronts and reduced carbon tax giving

80% probability of remaining below 2°C was also investigated in detail. A 10-year delay by all countries

would make 1.5°C impossible although 2°C would remain feasible (1.8°C with 50% probability)19. The

team's 1.5°C 50% scenario expressed the most ambitious assumptions considered reasonable, more

stringent options were not investigated.

In Mercure et al. (2018) and Pollitt et al. (2018) the major opportunity for decarbonisation is presented by

a substantial near-term green growth GDP and employment gain which applies mostly in fossil fuel

importing countries, reinforcing decarbonisation policies and actions. In exporting countries there are

generally negative impacts on GDP and employment. The primary challenges are political rather than

technological. The effects of non-action and delayed action by individual countries and groups of

countries were investigated. In all cases this had a negative economic effect in the near-term on the

country avoiding action, in other words the opposite of a 'free-riding' effect applies. This result applied to

all seven country groups considered in all 335 scenarios modelled, to at least ~2040. No country acting

alone pushed the median warming from 1.5°C significantly above 2°C. Of the major emitting countries,

only China's withdrawal pushed the median close to 2°C. Withdrawal of the USA alone without

entrainment of other countries had little effect on global temperature.

Key assumptions include a maximum available BECCS potential of 150 EJ/year; no new government

borrowing (with any income or cost resulting from additional policies being equalised by compensation

of general taxation); sufficiently rapid improvements in energy storage and grid technology to support the

energy transition; reductions in process emissions at similar rates to power sector emission reductions,

and coordinated political action. Net zero global emissions were assumed to be reached shortly before

2060 by extrapolation of modelled trends up to 2050. Carbon-cycle uncertainties were investigated in a

fully coupled, ESM driven by realistic emissions for a ~1.5°C threshold, finding that carbon cycle

processes explained around half the uncertainty in the Earth System warming response to emissions.

However, the key finding was that for strong mitigation, uncertainties dominated the mean response

patterns, as mentioned before.

Pollitt et al. (2018) pointed out that most IAMs are more pessimistic than the E3ME model, which is

based on a disequilibrium dynamic simulation paradigm in contrast to most IAMs, which belong to a

class of neo-classical equilibrium based models. The E3ME model is generally more optimistic about

strong mitigation and the potential for green growth and involves a greater range of policies than most

other models. As noted earlier in this report, most IAMs appear to under-estimate the potential for

reductions in energy demand.

19 This modeling activity focused on the policies needed to reduce CO2 emission from the energy sector, but did not

explicitly address the policies required to reduce CO2 process emissions (e.g., from cement) and CO2 emission from

deforestation. Their model captured the carbon cycle aspect of deforestation by applying RCP LUC maps to genie,

and process emissions were scaled to energy emissions.



19

Conventional IAMs have focused on determining the most economically efficient global energy system

compatible with a 2°C goal. These studies largely rely on global cost optimisation to set the level of

carbon taxation and on negative emissions. In the real world, climate policies vary widely across

countries and sectors. Regulations, subsidies, research programmes, and trade and investment frameworks

can all be combined to enhance diffusion of clean energy technologies, and to incentivise divestment from

high-emission alternatives. The E3ME-FTT-GENIE model uses observed technology trajectories,

together with a much wider portfolio of possible policy interventions, to estimate likely future pathways

of technology uptake. Another critical departure from conventional modelling is the inclusion of debt-

financed 'green growth' which is ruled out by most IAMs.

C) What are the societal and behavioural changes required to achieve these transformations and

their challenges?

Whitmarsh et. al. (2017)20, reported that attitudes often become more positive to technologies and policies

once they have been implemented, and people can experience the benefits and adapt to change. In

general, policies are likely to be resisted if seen as unfair or ineffective. Engagement processes are critical

to communicating benefits of action and implications of inaction; and for designing policies that are fair

and effective. Equally, engagement in technology design and siting decisions can improve outcomes

(including reducing opposition); and compensating communities where energy developments are sited is

also key.

• Societal and behavioural risks for the different mitigation strategies are centered on public opposition

to the requisite technology or policy. This is both for the supply side and the demand side (see details

below);

• Opportunities are focused on increasing public participation within mitigation policy-making and

action to improve decision quality, potentially reduce opposition to policies/technologies, and

generate pro-active engagement in a low-carbon transition. This includes (i) capitalising on public

support for sustainable energy sources and efficiency measures; and (ii) exploiting social influence

processes to help diffuse low-carbon innovations; and

• Engaging the public about carbon mitigation scenarios may influence behavioural intentions as well

as yielding important insights into public acceptability of transformative energy scenarios.

Supply side infrastructure

• Renewables: These are preferred as sources of energy, with nuclear and fossil fuels garnering the

least support (though cross-national variation). However, abstract support does not always translate

into local support due to challenges over siting of wind turbines, solar farms and hydroelectric plants,

largely due to risk perceptions or lack of engagement of local people in decision-making. Public

acceptance of large, energy infrastructures can be encouraged through early and substantive

engagement, as well as community benefits or ownership;

• Solar PV and small wind turbines: Householder adoption of solar PVs or small wind turbines is

driven primarily by financial considerations as well as a desire to be environmentally-friendly;

• Nuclear: Concerns remain high in many countries, especially following the nuclear disaster at

Fukushima. However, in U.S. and several other countries nuclear power remains relatively preferable

energy source where the benefits are viewed to outweigh the risks;

• Biomass energy: Comparatively under-researched, particularly in the configurations and scale

assumed in the 1.5ºC and 2ºC scenarios (large scale use of biomass energy and BECCS). Studies tend

to show lower awareness than with other renewables with most concerns related to sustainability,

local air pollution and impacts on land use, aesthetics and culture;

20 Whithmarsh et al. (2017) http://dx.doi.org/10.1098/rsta.2016.0376



20

• Carbon Capture and Storage (CCS): While CCS is integral to most low-carbon scenarios, there is

currently very low public awareness. The informed public have mixed views: positive about the

potential to reduce emissions and provide employment, but concerns about risks (e.g. leakage) and

that CCS is only a temporary solution that does not reduce fossil fuel dependence21.

Demand side technologies and strategies

• Energy efficiency (EE): In principle the public are positive about energy efficiency, but barriers exist

to the adoption of EE measures, e.g., initial cost, inconvenience, habit, and often resistance to

changing behaviours, especially indoor heating and transport.

• Energy consumption: Demand-side reduction through restrictions on energy services are often

resisted by individuals. Restrictions on flying are likely to be particularly contentious, especially

amongst those who are frequent flyers. Overall, there is more public support for ‘pull measures’, e.g.,

public transport, than ‘push measures’, e.g., increased taxes/tolls which may restrict individual freedom;

• Behaviour change: Behaviour change interventions have achieved energy savings of 5-10%. Policies

targeting organisations, habits, high-impact or multiple behaviours are likely to be most effective.

• Load-shifting: Acceptability of load-shifting measures varies by device and conditions: e.g., delayed

dishwasher start is largely accepted, but intervention in fridges/freezers or heating systems is not due

to comfort and health concerns. Many are concerned about data inaccuracies and privacy with smart

meters;

• Electric vehicles (EVs): Most of the public perceive the current generation of EVs as a ‘work in

progress’ and too costly, despite offering environmental benefits. Other barriers to adoption include

limited rapid charging infrastructure, leading to ‘range anxiety’. Given the importance of familiarity

to the adoption of new (vehicle) technologies, social networks may be key to EV promotion;

Circular economy

Circular economy measures can contribute to reducing emissions beyond what is included in projections

and in the Nationally Determined Contributions. Industrial reconfiguration, such as circular economy,

will need to be considered not only at business and market level, but also at the consumer level. A

successful circular economy will require consumers to shift their perspective from one where they are the

‘end of the line’ for a product to one where they are an active intermediary in a closed-loop system that

aims to reduce, reuse, or recycle and recover materials. According to some estimates, less than a tenth of

the material in circulation is reused or recycled, indicating a large potential in this area.

Disruptive low-carbon innovations

Wilson et.al. (2018) analyzed the potential of disruptive low-carbon innovations to contribute to

achieving the 1.5ºC and 2ºC goals (Table 2), and assessed the status of the mitigation options used in

IAMs and low-carbon disruptive technologies in the technology life-cycle, from basic research to

maturity (Figure 2).

• Consumers are largely regarded as an obstacle to climate change mitigation; yet there are many end-

use goods and services that are both potentially appealing for consumers and potentially emission-

reducing;

21 It should be noted that there is currently no successful operational experience of CCS on a power-station. The

small Boundary Dam project (110MW) has operational difficulties and is only capturing a small proportion of the

carbon dioxide it was designed to capture.



21

• The term ‘disruptive low-carbon innovation’ draws on business and management scholarship to

describe goods and services that offer novel attributes to consumers and that could become

mainstream to dislodge incumbent firms;

• Many disruptive low-carbon innovations could be identified at the fringes of mainstream markets

providing goods and services for mobility, food, housing, and cities;

• Novel attributes of disruptive low-carbon innovations of potential appeal to consumers include: (i)

versatility and diversity of functions, (ii) variety of choice, (iii) control and autonomy (iv),

relationships with others, (v) active involvement;

• Few, if any of these consumer-facing innovations are included or recognised in global systems

models of mitigation pathways; yet in-depth bottom-up studies find large emission-reduction

potentials from specific innovations; and

• Polices should recognise and enable the potential for disruptive low-carbon innovators to bring new

goods and services into mainstream markets.

Table 2: Potential Emissions Reductions of Disruptive Low-Carbon Innovations in the UK extrapolated

based on current preferences. Changes in preferences can lead to additional changes in emissions, both

reductions and increases.

Figure 2: Technology Life-Cycle for Mitigation Options in Global IAMs and Potentially Disruptive

Technologies.

PotentialDLCI Potentialannualemissionreductions

as%ofUKsectoral

emissions

mobility car-sharing 0.8to0.9MtCO2e 0.8-0.9%

e-bikes 0.04to0.08MtCO2e 0.04-0.08%

e-bikesharing 0.09MtCO2e 0.09%

mobility-as-a-service 1.4MtCO2e 1.4%

food

culturedmeat 0.02MtCO2e 0.03%

foodwastereduction 2.6to3.6MtCO2e 5.2-7.1%

urbanfarming 2.1MtCO2e 4.1%

reducedmeatindiet 0.7MtCO2e 1.4%



22

D) What are the differences in the global and regional impacts and risks on human-related systems

between global warming of 1.5°C and 2°C, from both the resulting climate change and the

pathways needed to limit temperature rise? And are there any other benefits other than avoided

impacts? What are the uncertainties surrounding estimates of the impacts and how well can we

distinguish between the impacts at 1.5°C and 2°C?

Warren et al. (2018a) projected the regional and global climate change impacts in 5 sectors resulting from

the baseline emissions scenario used in the IMAGE model compared with the 1.5°C and 2.0°C scenarios.

This results in a comparison of the impacts of two different stabilisation levels and for two different

probabilities. The uncertainty in climate projections is considered by using warming patterns from six

General Circulation Models (GCM). Table 3 shows the absolute differences between the global aggregate

impacts at different warming levels in 2100. Figure 3 shows the percentage impacts avoided going from

the 2°C scenario to the 1.5°C scenario. Figure 4 shows the time evolution of global aggregate economic

damages as %GDP loss in a scenario in which global annual mean temperature rise to 3.66°C above pre-

industrial levels, in comparison with scenarios in which warming is constrained to below 1.5°C or 2°C

with 66% probability. In the no policy baseline (red line), temperature rises by 3.66°C by 2100, resulting

in global GDP loss of 2.6% (5-95% percentile range 0.5-8.2%), as compared with 0.3% (0.1 – 0.5%) by

2100 in the 1.5°C scenario (blue line) and 0.5% (0.1-1.0%) in the 2°C scenario (green line).Key messages

include:

• In most sectors and regions risks are avoided by constraining warming to the lower stabilization

level. Specifically comparing risks at 1.5°C warming rather than 2°C above preindustrial levels:

• Across sectors, the % impacts avoided globally varies from -3 to +62%, taking into account the

uncertainties from use of alternative GCM patterns in downscaling;

• Avoided global economic damages of 22% (10-26%) accrue by constraining warming to 1.5°C rather

than 2°C; 90% (77-93%) by constraining warming to 1.5°C rather than 3.66°C, and 87% (74-91%) by

constraining warming to 2°C rather than 3.66°C;

• The largest avoided impacts are for fluvial flooding and the lowest are for malaria where risks

actually decline with warming in the global aggregate;

• Changes in risks vary across and within regions. Risks increase already in the 2050s for crop yield,

dengue (risks) and malaria (benefits);

• In most places, risks increase with warming, however, in some locations there are non-linearities, i.e.,

there are places where risks are lower than at present with warming of 1.5°C and then higher than at

present with 2°C warming (e.g. for malaria, where the risk decreases at 1.5ºC and increases again

above 2ºC). Non-monotonic changes in precipitation can contribute to these non-linearities, issues

such as heat stress, crop yields and drought which are function of both precipitation/humidity and

temperature change;

Warren et. al. (2018a), quantified uncertainties using six climate models from the CMIP5 archive and by

conducting sensitivity analysis to model assumptions and parameters. The ranges in table 3 reflect model

spread. In general, the analysis could distinguish between levels of impacts at the two levels of

warming. Using a measure of % impacts avoided (rather than absolute benefits) is more robust, since the

% impacts avoided is less uncertain than the absolute levels of risk.

Table 3 shows the absolute differences between the global aggregate impacts at different warming levels

in 2100. Risks avoided are positive numbers. Error bars indicate the range of uncertainty associated with

the use of alternative regional climate change patterns associated with the different models.



23

time Metric (with units) observed

climate

(1961-

1990) vs

1.5 (66%)

1.5 (66%)

vs 2 (66%)

1.5 (66%) vs

3.66

2 (66%) vs

3.66

Agriculture % Crop Yield Loss 3.7

(3.6, 3.9)

1.4

(1.3, 1.5)

9.3

(9.0, 9.8)

7.9

(7.6, 8.4)

Economy Damages as %GDP

loss in 2100

NPV of impacts

($trillion)

0.28

(0.11, 0.53)

54

(14, 121)

0.18

(0.02, 0.45)

15

(1, 43)

2.34

(0.36, 7.66)

488

(36, 1690)

2.16

(0.34, 7.21)

482

(34, 1663)

Coastal

Flooding

Cumulative land loss

due to submergence

(x103 / yr)

Not

available

14.0

(8.4-20.1)

78.9 (48.8-

108.5)

64.9 (39.5-

88.3)

Coastal

Flooding

People exposed to

coastal flood risk

(millions/yr)

Not

available

8.2 (4.6-7.3) 35.3 (26.4-

38.2)

27.1 (21.8-

30.9)

Fluvial

Flooding

Population living in

the modelled

inundation areas in

which the discharge

exceeds the 100-year

flood in 1961-1990

(tens of millions)

30.1

(6.6, 66.2)

31.1

(8.4, 56.4)

279.0

(101.7, 489.8)

247.9

(93.3, 433.4)

Drought Million people at risk

from a -1.5 SPEI 12

event in any given

month

63.7

(48.5, 95.5)

22.8

(17.3, 34.0)

125.4

(96.7, 125.4)

102.6

(79.4, 129.7)

Heat stress Hundred Million

People exposed to

moderate to extreme

heat injury risk

12.1

(10.9, 14.3)

3.9

(3.3, 4.8)

21.7

(20.6, 23.2)

17.8

(17.3, 18.4)

Malaria Million People at

risk of infection

456.7

(432.0,

480.8)

-9.9

(-20.7, -0.9)

-87.3

(-165.5, -25.4)

-77.4

(-144.8, -24.5)

Dengue Million People at

risk of infection

7.3

(6.8, 8.2)

0.8

(0.6, 1.2)

5.2

(3.8, 7.8)

4.4

(3.2, 6.7)



24

Figure 3: Percentage Impacts Avoided Going from 2ºC and 1.5ºC scenarios

Figure 4: Global Aggregated Damage as a % of GDP for Different Scenarios

Climate Change and Biodiversity

Warren et al. (2018b), reported that considering climate change alone, limiting global warming to 1.5ºC

above pre-industrial levels avoids half the risks associated with warming of 2ºC for plants, animals, and

insects in terms of climate change induced range loss. Areas which benefit the most from constraining

warming to 1.5ºC as compared to 2ºC in terms of avoiding declines in species richness are Southern

Africa, Southern Europe and Australia.



25

They present results from the first global scale assessment of climate change impacts on 19,848 species of

insects and found that 20±10% of these are projected to lose over half their range at 2ºC and 9±6% at

1.5ºC, even when the potential for species to disperse at a realistic rate to track their shifting climate

envelope. Given recent observed declines in insects, they found that limiting warming to 1.5ºC will be

important in preserving ecosystem functioning and services, especially those provided by insects such as

pollination, detrivory, herbivory, and nutrient cycling. These declines would also impact on insectivores

and their predators.

Corresponding analyses for 12,429 species of mammals, birds and reptiles and amphibians show that

8±5% of animals are projected to lose over half their range at 2ºC and 4±3% at 1.5ºC; and 16±10% of

73,224 plant species are projected to lose over half their range at 2ºC and 8±5% at 1.5ºC. Hence overall

across all taxa analyzed limiting warming to 1.5ºC compared to 2ºC reduces climate-change induced

geographical range loss by approximately 50%.

The IMPALA project quantified the terrestrial land areas potentially acting as climate refugia for 80,000

terrestrial plants, birds, mammals, reptiles and amphibians. Climate refugia are defined as areas where

>75% of the species currently modelled are projected to remain under the changed climate, according to

more than half of the regional climate change models. Warren et al. (2018b) used the IMPALA model to

qualitatively assess the implications of temperature overshoot, in particular highlighting how an overshoot

of half a degree (to 2°C as opposed to 1.5°C) would be expected to have significant negative effects on

biodiversity in terms of species range loss; and that if the overshoot persists for sufficiently long, species

that disperse rapidly might ‘over’ adapt by moving spatially to geographical areas that become newly

suitable for them, and then may need to retreat from these areas later as warming or precipitation changes

ameliorate. For species that do not disperse rapidly and which would be negatively affected by 2°C

warming, the longer the overshoot the less likely they are to be able survive in situ until the temperature

returns to 1.5°C.

The IMPALA model was also used to explore the role of natural adaptation by dispersal, showing how

important this is in allowing species to persist under climate change. This is particularly important for

birds, mammals, butterflies and dragonflies. Therefore, the slower the rate of temperature rise, and the

later we reach or pass the 1.5°C threshold, the lower are the impacts of climate change on biodiversity.

In the IMPALA project, uncertainties were explored associated with alternative projections of regional

climate change associated with 21 alternative regional climate change patterns from CMIP5. Whilst there

are uncertainties about the precise values of species’ range loss, such that the lowest value of range loss

for a species under 2ºC warming is often lower than the highest value under 1.5ºC warming, the ensemble

means across the regional climate model patterns consistently differ: there is no difficulty in detecting a

consistent difference between 1.5ºC /2ºC warming when using each individual GCM and hence the

ensemble as a whole.

Climate Change and Human Health

Andrews et al. (2018) reported that extreme risks to population health from heat stress appear across

many tropical and sub-tropical regions in response to future global warming of + 1.5ºC, and become

widespread in these regions around global warming of + 2.5ºC – 3ºC. The exact population exposed

depends on the specific choice of thresholds, but conservative estimates are in the tens of millions, while

top-end estimates are in the billions of people. Both workability and survivability are affected, however

more people are exposed to workability limits. Population exposed can increase suddenly within one

decade due to the non-linear interactions between regional climate variability and excessive heat stress

thresholds.

Climate Change and Sea Level Rise and Ocean Acidity



26

Nicholls et al., (2018) reported that the proportion of global population exposed to sea-level rise in 2300

was projected at 2.0% for an aggressive mitigation scenario (1.5°C) and 5.4% for the non-mitigation

policy scenario (RCP8.5). Table 4 quantifies, with uncertainty limits, projected changes in sea level and

ocean ph for the 1.5°C, 2°C and RCP 8.5 scenarios, compared to a baseline of 1986-2005. Even though

temperature stabilizes in the 1.5°C and 2°C scenarios prior to 2100, sea levels continue to rise for several

more centuries, hence the need to quantify projected levels in 2300. Small islands, deltas and cities,

especially in India and China (Figure 5) are highly vulnerable to projected increases in sea level and

should consider preparing adaptation plans.

Table 4. Summary results of the WASP Earth System Model for global mean temperature, global mean

sea-level rise and ocean pH and the two stabilisation scenarios (1.5ºC and 2.0ºC) and the reference

unmitigated (RCP8.5) emissions scenario (projected temperatures shown in the table for 2050, 2100 and

2300). Results include the ensemble mean ± standard deviation and the 90% range (5th percentile to 95th

percentile) in brackets. Note that the 1.5ºC pathway stabilises temperature at 2045, and the 2.0ºC pathway

stabilises temperature at 2065.

Time Global mean temperature

(relative to pre-industrial)

(ºC)

Sea-level rise

(relative to 1986-2005

average) (m)

Ocean pH

1.5ºC 2.0ºC RCP8.5 1.5ºC 2.0ºC RCP8.5 1.5ºC 2.0ºC RCP8.5

1986-

2005

0.8±0.2 (0.7-1.3) 0.0 8.11±0.00 (8.10-8.11)

2050 1.5 ±

0.2

(1.2-

1.8)

1.8 ±

0.3

(1.4-

2.2)

2.1 ±

0.5

(1.6-

3.2)

0.21

± 0.04

(0.14-

0.28)

0.23

± 0.04

(0.17-

0.30)

0.26

± 0.04

(0.19-

0.32)

8.06 ±

0.04

(8.03-

8.15)

8.01 ±

0.04

(7.97-

8.11)

7.96 ±

0.01

(7.95-

7.97)

2100 1.5±0.1

(1.2-

1.6)

2.0±0.2

(1.8-

2.3)

4.1 ±

1.0

(3.0-

6.3)

0.39 ±

0.09

(0.24-

0.54)

0.49 ±

0.10

(0.31 -

0.65)

0.72 ±

0.11

(0.54-

0.91)

8.08 ±

0.04

(8.04 -

8.16)

8.02 ±

0.06

(7.95-

8.13)

7.75 ±

0.01

(7.74-

7.76)

2300 1.5±0.1

(1.4-

1.5)

2.0±0.1

(1.9-

2.0)

8.8±3.1

(5.5-

14.8)

0.89 ±

0.23

(0.53 -

1.27)

1.17 ±

0.29

(0.71 -

1.65)

3.65±0.8

9

(2.40-

5.27)

8.09 ±

0.04

(8.02 -

8.15)

8.04 ±

0.06

(7.95 –

8.13)

7.45±0.0

0

(7.74-

7.75)



27

Figure 5: Number of People Flooded Annually (million per year) in 2100 for the 1.5°C, 2°C and RCP 8.5

scenarios (50th percentile) under SSP2, Assuming no Additional Adaptation

Jevrejeva et al. (2018) estimated a global sea level rise up to 52 cm (25 to 87) and up to 63 cm (27 to 112)

for a temperature rise of 1.5°C and 2.0°C by 2100 respectively. The additional 11 cm of sea level rise

between the 1.5 ºC and the 2 ºC scenario is projected to result in additional global annual flood costs of

US$ 1.5 trillion per year (0.25% of global GDP) without adaptation. Flood cost for UK is projected to

increase from 2.5% of GDP (1.5°C) to 4% GDP(2°C). Failure to meet either of the 1.5ºC and 2ºC goals

will clearly lead to greater economic costs and higher levels of costal risk worldwide.

Coastal sea level rise generally exceeds the global average, with exceptions of coastline in the areas close

to Greenland and Antarctic ice sheets. The largest differences between 1.5ºC and 2ºC scenarios along

coastlines are ~15 cm for median projections (up to 20 cm at 95th percentile) and occur for the USA east

coast and the small-island nations in the Pacific and Indian oceans.

By 2200 global sea level rise projections are up to 1m (50%) and 1.69m (95%) with 1.5ºC and 1.32m

(50%) and 2.22 m (95%) with 2ºC. The difference in sea level rise with warming of 1.5ºC and 2ºC could

be up to 0.32m for median (0.22-0.32) and up to 0.53m for the 95% percentile (0.37-0.53), almost 1/3 of

possible sea level rise of 1.0m (1.5ºC) and 1.32m (2ºC) by 2200. The largest gap in our understanding of

future sea level changes is due to Greenland and Antarctic ice sheet response to future warming.

Brown et al (2018), however, reported that the projected changes in 2100 overlap for sea-level and flood-

exposure for the 1.5ºC and 2.0°C scenarios, with the differences being small and hard to distinguish.

While the differences do begin to grow after 2100, the projected differences between the 1.5°C and 2.0°C

scenarios are small in comparison to the differences between either of these scenarios and the RCP8.5

scenario.



28

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30

Acknowledgements

This summary report is based on publications, some in draft form, from a number of researchers funded

by BEIS and NERC programmes examining the implications of global warming of 1.5°C and 2°C project.

The authors gratefully acknowledge access to early draft of publications and contributions of headline

findings from Bill Collins, Peter Cox, Pierre Friedlingstein, Jonathan Gregory, Gary Hayman, Paul

Halloran, and Svetlana Jevrejeva, as well as additional input from:

Sally Brown, University of Southampton and the Tyndall Centre

Neil Edwards, Open University

David Gernaat, PBL Netherlands Environmental Assessment Agency and Utrecht University

Phil Goodwin, University of Southampton

Clair Gough, University of Manchester and the Tyndall Centre

Anna Harper, University of Exeter

Emma Littleton, University of Exeter

Maria Sharmina, University of Manchester and the Tyndall Centre

Detlef van Vuuren, PBL Netherlands Environmental Assessment Agency and Utrecht University

Naomi Vaughan, University of East Anglia and the Tyndall Centre

Rachel Warren, University of East Anglia and the Tyndall Centre

Andrew Welfle, University of Manchester and the Tyndall Centre

Lorraine Whitmarsh, Cardiff University and the Tyndall Centre

Colin Whittle, Cardiff University and the Tyndall Centre

Charlie Wilson, University of East Anglia and the Tyndall Centre

We also thank Jolene Cook, Stephen Forden, Julie Maclean and others at BEIS for comments on previous

drafts of this summary report.

The Tyndall Centre project that underpins large parts of this report was managed by Asher Minns from

the Tyndall Centre at UEA, and supported by Alfie Kirk.



31

Annex 1

BEIS requested that the research addressed the following series of questions. Questions 1bis, 2bis, 3bis,

4bis and 6 were requested at a later date than questions 1-5. Unfortunately, the research conducted does

not allow question 6 to be answered.

Question 1: What are the implications of different interpretations of the 1.5ºC goal for impacts and

emissions pathways?

Question 1bis: What are the global and regional implications for peaking emissions in a 1.5ºC scenario,

and how do they differ from 2.0ºC?

Question 2: What global and regional rates of decarbonization are needed and when would net zero

emissions need to be reached to limit temperature rise to 1.5ºC compared to 2.0ºC, and how can these be

achieved? What are the key assumptions?

Question 3: What are the global and regional opportunities, challenges and risks of different mitigation

strategies and technologies to limit temperature rise to 2°C and 1.5°C? What are the major uncertainties in

these?

Question 2bis: What are the societal and behavioural attitudes and changes required to achieve these low-

carbon transformations and their challenges?

Question 2bisa: What are the costs for different mitigation pathways, and what major technological

developments are required and feasible are they?

Question 4: What are the differences in the global and regional impacts and risks on human-related

systems between global warming of 1.5°C and 2ºC, from both the resulting climate change and the

pathways needed to limit temperature rise?

Question 4bis: And are there any other benefits other than avoided impacts?

Question 5: What are the uncertainties surrounding estimates of the impacts and how well can we

distinguish between the impacts at 1.5°C and 2ºC?

Question 6: What are the differences in probabilities of extreme temperature rise (i.e., risk of 4ºC+) under

a 1.5ºC vs 2.0ºC 66% trajectory? Do they vary depending on how 1.5ºC vs 2.0ºC are achieved? What are

the differences in the risk of tipping points and key feedbacks between 1.5ºC vs 2.0ºC?

Tyndall Working Paper series

2000 - 2018

The Tyndall Centre working paper series presents results from research which are mature enough to be submitted to a refereed journal, to a sponsor, to a major conference or to the editor of a book. The

intention is to enhance the early public availability of research undertaken by the Tyndall family of

researchers, students and visitors. They can be downloaded from the Tyndall Website at:

http://www.tyndall.ac.uk/publications/working_papers/working_papers.shtml

The accuracy of working papers and the conclusions reached are the responsibility of the author(s)

alone and not the Tyndall Centre.

Papers available in this series are:

• Watson, R. T.; Le Quéré, C. (2018). The

Implications of global warming of 1.5ºC and 2ºC Summary Report Tyndall Working Paper 164

• Wilson, C. (2017). Disruptive Low Carbon Innovation Workshops: Synthesis Report Tyndall Working Paper 165

• Nunes, A. R.; (2016) Assets for health: linking vulnerability, resilience and adaptation to climate change Tyndall Working Paper 163

• Rayner, T.; Minns, A; (2015) The challenge of communicating unwelcome climate messages Tyndall Working Paper 162

• Le Quéré, C., Capstick, S., Corner, A., Cutting, D., Johnson, M., Minns, A., Schroeder, H., Walker-Springett, K., Whitmarsh, L., Wood, R.; (2015) Towards

a culture of low-carbon research for

the 21st Century Tyndall Working Paper

161

• Wilson, C.; Crane, L.; Chryssochoidis, G.; (2014) Why do people decide to renovate their homes to improve energy efficiency? Tyndall Working Paper 160

• Baker, L.; Linnea Wlokas, H.; (2014)South Africa's Renewable Energy

Procurement: A New Frontier TyndallWorking Paper 159;

• Potten, D. (2013) The Green ClimateFund and Lessons from other GlobalFunds’ Experience Tyndall Working

Paper 158;

• Martin, M.; Thornley, P. (2013) The

potential for thermal storage toreduce the overall carbon emissionsfrom district heating systems Tyndall

Working Paper 157;

• Diaz-Rainey, I; Finegan, A; Ibikunle, G;

Tulloch, DJ; (2012) InstitutionalInvestment in the EU ETS TyndallWorking Paper 156;

• Kelly, S; Crawford-Brown, D; Pollitt, M.;(2012) Building Performance

evaluation and certification in the UK:Is SAP fit for purpose? Renewable andSustainable Energy Reviews Tyndall

Working Paper 155;

• Kelly, S.; Shipworth, M.; Shipworth, D.;

Gentry, M.; Wright, A.; Pollitt, M.;Crawford-Brown, D.; Lomas, K.; (2012) Apanel model for predicting the

http://www.tyndall.ac.uk/publications/working_papers/working_papers.shtml

diversity of internal temperatures

from English dwellings Tyndall Working Paper 154;

• Bellamy, R.; Chilvers, J.; Vaughan, NE.; Lenton, T M.; (2012) AppraisingGeoengineering Tyndall Working Paper

153;

• Nordhagen, S.; Calverley, D.; Foulds, C.;

Thom, L.; Wang, X.; (2012) Credibility inclimate change research: a reflexiveview Tyndall Working Paper 152;

• Milman, A.; Bunclark, L.; Conway, D.and Adger, W N (2012) Adaptive

Capacity of Transboundary Basins inthe Mediterranean, the Middle Eastand the Sahel Tyndall Working Paper

151;

• Upham, P.; Kuttapan, V., and Tomeic, J.

(2012) Sustainable livelihoods andcultivation of Jatropha curcas forbiodiesel in India: reflections on

alternative agronomic models TyndallWorking Paper 150;

• Shen, W.(2011) Understanding thedominance of unilateral CDMs inChina: Its origins and implications for

governing carbon markete TyndallWorking Paper 149;

• Mercure, JF.(2011) Global electricity

technology substitution model withinduced technological change Tyndall

Working Paper 148;• Gough, C., and Upham, P.(2010)Biomass energy with carbon capture

and storage (BECCS): a review TyndallWorking Paper 147;

• Kebede, A., Nicholls R. J., Hanson S.and Mokrech, M.(2010) Impacts ofClimate Change and Sea-Level Rise: A

Preliminary Case Study of Mombasa,Kenya. Tyndall Working Paper 146;

• Dendler, L.(2010) Sustainability MetaLabelling: A Discussion of Potential

Implementation Issues. Tyndall

Working Paper 145;

• McLachlan, C.(2010) Tidal stream

energy in the UK: Stakeholderperceptions study. Tyndall WorkingPaper 144;

• Upham, P., and Julia Tomei (2010)

Critical Stakeholder Perceptions ofCarbon and Sustainability Reporting inthe UK Renewable Transport Fuel

Obligation. Tyndall Centre Working Paper143;

• Hargreaves, T. (2010) The Visible

Energy Trial: Insights from QualitativeInterviews. Tyndall Working Paper 141;

• Newsham, A., and D. Thomas. (2009)Agricultural adaptation, localknowledge and livelihoods

diversification in North-CentralNamibia. Tyndall Working Paper 140;

• Starkey, R.. (2009) Assessingcommon(s) arguments for an equalper capita allocation. Tyndall Working

Paper 139;

• Bulkeley, H., and H. Schroeder. (2009)

Governing Climate Change Post-2012:The Role of Global Cities – Melbourne.Tyndall Working Paper 138;

• Seyfang, G., I. Lorenzoni, and M. Nye.,(2009) Personal Carbon Trading: a

critical examination of proposals forthe UK. Tyndall Working Paper 136.

• HTompkins E. L, Boyd E., Nicholson-ColeS, Weatherhead EK, Arnell N. W., AdgerW. N., (2009) An Inventory of

Adaptation to climate change in theUK: challenges and findings: TyndallWorking Paper 135;

• Haxeltine A., Seyfang G., (2009)Transitions for the People: Theory and

Practice of ‘Transition’ and‘Resilience’ in the UK’s TransitionMovement: Tyndall Working Paper 134;

• Tomei J., Upham P., (2009)Argentinean soy based biodiesel: anintroduction to production and

impacts: Tyndall Working Paper 133;

• Whitmarsh L, O'Neill S, Seyfang G.,Lorenzoni I., (2008) Carbon Capability:what does it mean, how prevalent is

it, and how can we promoteit?: Tyndall Working Paper 132;

• Huang Y., Barker T., (2009)Does Geography Matter for the CleanDevelopment Mechanism? :

Tyndall Working Paper 131;

• Huang Y., Barker T., (2009)

The Clean Development Mechanismand Sustainable Development: APanel Data Analysis: Tyndall Working

Paper 130;

• Dawson R., Hall J, Barr S, Batty M.,

Bristow A, Carney S, Dagoumas, A., EvansS., Ford A, Harwatt H., Kohler J., Tight M,

(2009) A blueprint for the integratedassessment of climate change incities: Tyndall Working Paper 129;

• Carney S, Whitmarsh L, Nicholson-ColeS, Shackley S., (2009) A Dynamic

Typology of Stakeholder Engagementwithin Climate Change Research:Tyndall Working paper 128;

• Goulden M, Conway D, Persechino A.,(2008) Adaptation to climate change in

international river basins in Africa: areview: Tyndall Working paper 127;

• Bows A., Anderson K., (2008)A bottom-up analysis of includingaviation within the EU’s Emissions

Trading Scheme: Tyndall Working Paper126;

• Al-Saleh Y., Upham P., Malik K., (2008)Renewable Energy Scenarios for theKingdom of Saudi Arabia: Tyndall

Working Paper 125

• Scrieciu S., Barker T., Smith V., (2008)

World economic dynamics andtechnological change: projectinginteractions between economic output

and CO2 emissions :Tyndall WorkingPaper 124

• Bulkeley H, Schroeder H., (2008)Governing Climate Change Post-2012:

The Role of Global Cities - London:Tyndall Working Paper 123• Schroeder H., Bulkeley H, (2008)

Governing Climate Change Post-2012:The Role of Global Cities, Case-Study:Los Angeles: Tyndall Working Paper 122

• Wang T., Watson J, (2008) CarbonEmissions Scenarios for China to

2100: Tyndall Working Paper 121

• Bergman, N., Whitmarsh L, Kohler J.,

(2008) Transition to sustainabledevelopment in the UK housingsector: from case study to model

implementation: Tyndall Working Paper120

• Conway D, Persechino A., Ardoin-BardinS., Hamandawana H., Dickson M, DieulinC, Mahe G, (2008) RAINFALL AND

WATER RESOURCES VARIABILITY INSUB-SAHARAN AFRICA DURING THE20TH CENTURY: Tyndall Centre Working

Paper 119

• Starkey R., (2008) Allocating

emissions rights: Are equal shares,fair shares? : Tyndall Working Paper 118

• Barker T., (2008) The Economics ofAvoiding Dangerous Climate Change:Tyndall Centre Working Paper 117

• Estrada M, Corbera E., Brown K, (2008)How do regulated and voluntary

carbon-offset schemes compare?:Tyndall Centre Working Paper 116

• Estrada Porrua M, Corbera E., Brown K,(2007) REDUCING GREENHOUSE GASEMISSIONS FROM DEFORESTATION

IN DEVELOPING COUNTRIES:

REVISITING THE ASSUMPTIONS:

Tyndall Centre Working Paper 115

• Boyd E., Hultman N E., Roberts T.,

Corbera E., Ebeling J., Liverman D, Brown K, Tippmann R., Cole J., Mann P, Kaiser M., Robbins M, (2007) The Clean

Development Mechanism: An assessment of current practice and future approaches for policy: Tyndall

Centre Working Paper 114

• Hanson, S., Nicholls, R., Balson, P.,

Brown, I., French, J.R., Spencer, T., Sutherland, W.J. (2007) Capturing coastal morphological

change within regional integrated assessment: an outcome-driven fuzzy logic approach: Tyndall Working Paper

No. 113

• Okereke, C., Bulkeley, H. (2007)

Conceptualizing climate change governance beyond the international regime: A review of four theoretical

approaches: Tyndall Working Paper No. 112

• Doulton, H., Brown, K. (2007) ‘Ten years to prevent catastrophe’? Discourses of climate change and

international development in the UK press: Tyndall Working Paper No. 111

• Dawson, R.J., et al (2007) Integrated analysis of risks of coastal flooding and cliff erosion under scenarios of

long term change: Tyndall Working Paper No. 110

• Okereke, C., (2007) A review of UK FTSE 100 climate strategy and a framework for more in-depth analysis

in the context of a post-2012 climate regime: Tyndall Centre Working Paper 109

• Gardiner S., Hanson S., Nicholls R., Zhang Z., Jude S., Jones A.P., et al (2007)

The Habitats Directive, Coastal Habitats and Climate Change – Case

Studies from the South Coast of the

UK: Tyndall Centre Working Paper 108

• Schipper E. Lisa, (2007) Climate

Change Adaptation and Development: Exploring the Linkages: Tyndall Centre Working Paper 107

• Okereke C., Mann P, Osbahr H, (2007) Assessment of key negotiating issues

at Nairobi climate COP/MOP and what it means for the future of the climate regime: Tyndall Centre Working Paper

No. 106

• Walkden M, Dickson M, (2006) The

response of soft rock shore profiles to increased sea-level rise. : Tyndall Centre Working Paper 105

• Dawson R., Hall J, Barr S, Batty M., Bristow A, Carney S, Evans E.P., Kohler J.,

Tight M, Walsh C, Ford A, (2007) A blueprint for the integrated assessment of climate change in

cities. : Tyndall Centre Working Paper 104

• Dickson M., Walkden M., Hall J., (2007) Modelling the impacts of climate change on an eroding coast over the

21st Century: Tyndall Centre Working Paper 103

• Klein R.J.T, Erickson S.E.H, Næss L.O,

Hammill A., Tanner T.M., Robledo, C., O’Brien K.L.,(2007) Portfolio screening

to support the mainstreaming of adaptation to climatic change into development assistance: Tyndall Centre

Working Paper 102

• Agnolucci P., (2007) Is it going to

happen? Regulatory Change and Renewable Electricity: Tyndall Centre Working Paper 101

• Kirk K., (2007) Potential for storage of carbon dioxide in the rocks beneath

the East Irish Sea: Tyndall Centre Working Paper 100

• Arnell N.W., (2006) Global impacts of

abrupt climate change: an initial

assessment: Tyndall Centre Working Paper 99

• Lowe T.,(2006) Is this climate porn? How does climate change communication affect our perceptions

and behaviour?, Tyndall Centre Working Paper 98

• Walkden M, Stansby P,(2006) The effect of dredging off Great Yarmouth on the wave conditions and erosion of

the North Norfolk coast. Tyndall Centre Working Paper 97

• Anthoff, D., Nicholls R., Tol R S J, Vafeidis, A., (2006) Global and regional

exposure to large rises in sea-level: a sensitivity analysis. This work was prepared for the Stern Review on the

Economics of Climate Change: Tyndall Centre Working Paper 96

• Few R., Brown K, Tompkins E. L, (2006) Public participation and climate change adaptation, Tyndall Centre

Working Paper 95 • Corbera E., Kosoy N, Martinez Tuna M,

(2006) Marketing ecosystem services through protected areas and rural communities in Meso-America:

Implications for economic efficiency, equity and political legitimacy, Tyndall Centre Working Paper 94

• Schipper E. Lisa, (2006) Climate Risk, Perceptions and Development in

El Salvador, Tyndall Centre Working Paper 93

• Tompkins E. L, Amundsen H, (2005) Perceptions of the effectiveness of the United Nations Framework Convention

on Climate Change in prompting behavioural change, Tyndall Centre Working Paper 92

• Warren R., Hope C, Mastrandrea M, Tol R S J, Adger W. N., Lorenzoni I., (2006)

Spotlighting the impacts functions in

integrated assessments. Research Report Prepared for the Stern Review on the Economics of Climate Change,

Tyndall Centre Working Paper 91 • Warren R., Arnell A, Nicholls R., Levy P

E, Price J, (2006) Understanding the regional impacts of climate change: Research Report Prepared for the

Stern Review on the Economics of Climate Change, Tyndall Centre Working Paper 90

• Barker T., Qureshi M, Kohler J., (2006)

The Costs of Greenhouse Gas Mitigation with Induced Technological Change: A Meta-Analysis of Estimates

in the Literature, Tyndall Centre Working Paper 89

• Kuang C, Stansby P, (2006) Sandbanks for coastal protection: implications of sea-level rise. Part 3:

wave modelling, Tyndall Centre Working Paper 88

• Kuang C, Stansby P, (2006) Sandbanks for coastal protection: implications of sea-level rise. Part 2:

current and morphological modelling, Tyndall Centre Working Paper 87

• Stansby P, Kuang C, Laurence D, Launder B, (2006) Sandbanks for coastal protection: implications of sea-level

rise. Part 1: application to East Anglia, Tyndall Centre Working Paper 86

• Bentham M, (2006) An assessment of carbon sequestration potential in

the UK – Southern North Sea case study: Tyndall Centre Working Paper 85

• Anderson K., Bows A., Upham P., (2006) Growth scenarios for EU & UK aviation: contradictions with climate

policy, Tyndall Centre Working Paper 84 • Williamson M., Lenton T., Shepherd J.,

Edwards N, (2006) An efficient

numerical terrestrial scheme (ENTS)

for fast earth system modelling, Tyndall Centre Working Paper 83

• Bows, A., and Anderson, K. (2005) An analysis of a post-Kyoto climate policy model, Tyndall Centre Working Paper 82

• Sorrell, S., (2005) The economics of energy service contracts, Tyndall Centre

Working Paper 81 • Wittneben, B., Haxeltine, A., Kjellen,

B., Köhler, J., Turnpenny, J., and Warren, R., (2005) A framework for assessing the political economy of post-2012

global climate regime, Tyndall Centre Working Paper 80

• Ingham, I., Ma, J., and Ulph, A. M. (2005) Can adaptation and mitigation be complements?, Tyndall Centre

Working Paper 79 • Agnolucci,. P (2005) Opportunism

and competition in the non-fossil fuel obligation market, Tyndall Centre Working Paper 78

• Barker, T., Pan, H., Köhler, J., Warren., R and Winne, S. (2005) Avoiding

dangerous climate change by inducing technological progress: scenarios using a large-scale econometric model,

Tyndall Centre Working Paper 77 • Agnolucci,. P (2005) The role of

political uncertainty in the Danish renewable energy market, Tyndall Centre Working Paper 76

• Fu, G., Hall, J. W. and Lawry, J.

(2005) Beyond probability: new methods for representing uncertainty in projections of future climate, Tyndall

Centre Working Paper 75 • Ingham, I., Ma, J., and Ulph, A. M.

(2005) How do the costs of adaptation affect optimal mitigation when there is uncertainty, irreversibility and

learning?, Tyndall Centre Working Paper

74 • Walkden, M. (2005) Coastal

process simulator scoping study, Tyndall Centre Working Paper 73

• Lowe, T., Brown, K., Suraje Dessai, S., Doria, M., Haynes, K. and Vincent., K (2005) Does tomorrow ever come?

Disaster narrative and public perceptions of climate change, Tyndall Centre Working Paper 72

• Boyd, E. Gutierrez, M. and Chang, M. (2005) Adapting small-scale CDM sinks

projects to low-income communities, Tyndall Centre Working Paper 71

• Abu-Sharkh, S., Li, R., Markvart, T., Ross, N., Wilson, P., Yao, R., Steemers, K., Kohler, J. and Arnold, R. (2005) Can

Migrogrids Make a Major Contribution to UK Energy Supply?, Tyndall Centre Working Paper 70

• Tompkins, E. L. and Hurlston, L. A. (2005) Natural hazards and climate

change: what knowledge is transferable?, Tyndall Centre Working Paper 69

• Bleda, M. and Shackley, S. (2005) The formation of belief in climate

change in business organisations: a dynamic simulation model, Tyndall Centre Working Paper 68

• Turnpenny, J., Haxeltine, A. and O’Riordan, T., (2005) Developing

regional and local scenarios for climate change mitigation and

adaptation: Part 2: Scenario creation, Tyndall Centre Working Paper 67

• Turnpenny, J., Haxeltine, A., Lorenzoni, I., O’Riordan, T., and Jones, M., (2005) Mapping actors involved in

climate change policy networks in the UK, Tyndall Centre Working Paper 66

• Adger, W. N., Brown, K. and

Tompkins, E. L. (2004) Why do resource managers make links to stakeholders at other scales?, Tyndall Centre Working

Paper 65 • Peters, M.D. and Powell, J.C. (2004)

Fuel Cells for a Sustainable Future II, Tyndall Centre Working Paper 64

• Few, R., Ahern, M., Matthies, F. and Kovats, S. (2004) Floods, health and climate change: a strategic review,

Tyndall Centre Working Paper 63 • Barker, T. (2004) Economic theory

and the transition to sustainability: a comparison of approaches, Tyndall Centre Working

Paper 62 • Brooks, N. (2004) Drought in the

African Sahel: long term perspectives and future prospects, Tyndall Centre Working Paper 61

• Few, R., Brown, K. and Tompkins, E.L. (2004) Scaling adaptation: climate

change response and coastal management in the UK, Tyndall Centre Working Paper 60

• Anderson, D and Winne, S. (2004) Modelling Innovation and Threshold

Effects In Climate Change Mitigation, Tyndall Centre Working Paper 59

• Bray, D and Shackley, S. (2004) The Social Simulation of The

Public Perceptions of Weather Events and their Effect upon the Development

of Belief in Anthropogenic Climate Change, Tyndall Centre Working Paper 58

• Shackley, S., Reiche, A. and Mander, S (2004) The Public Perceptions of Underground Coal Gasification (UCG):

A Pilot Study, Tyndall Centre Working Paper 57

• Vincent, K. (2004) Creating an

index of social vulnerability to climate change for Africa, Tyndall Centre Working Paper 56

• Mitchell, T.D. Carter, T.R., Jones,

.P.D, Hulme, M. and New, M. (2004) A comprehensive set of high-resolution grids of monthly climate for Europe

and the globe: the observed record (1901-2000) and 16 scenarios (2001-2100), Tyndall Centre Working Paper 55

• Turnpenny, J., Carney, S., Haxeltine, A., and O’Riordan, T. (2004)

Developing regional and local scenarios for climate change mitigation and adaptation Part 1: A

framing of the East of England Tyndall Centre Working Paper 54

• Agnolucci, P. and Ekins, P. (2004) The Announcement Effect And Environmental Taxation Tyndall Centre

Working Paper 53 • Agnolucci, P. (2004) Ex Post

Evaluations of CO2 –Based Taxes: A Survey Tyndall Centre Working Paper 52

• Agnolucci, P., Barker, T. and Ekins, P. (2004) Hysteresis and Energy Demand: the Announcement Effects

and the effects of the UK Climate Change Levy Tyndall Centre Working Paper 51

• Powell, J.C., Peters, M.D., Ruddell, A. and Halliday, J. (2004) Fuel Cells for a

Sustainable Future? Tyndall Centre Working Paper 50

• Awerbuch, S. (2004) Restructuring our electricity networks to promote

decarbonisation, Tyndall Centre Working Paper 49

• Pan, H. (2004) The evolution of economic structure under technological development, Tyndall


• Berkhout, F., Hertin, J. and Gann, D. M., (2004) Learning to adapt: Organisational adaptation to climate

change impacts, Tyndall Centre Working Paper 47

• Watson, J., Tetteh, A., Dutton, G., Bristow, A., Kelly, C., Page, M. and Pridmore, A., (2004) UK Hydrogen

Futures to 2050, Tyndall Centre Working Paper 46

• Purdy, R and Macrory, R. (2004) Geological carbon sequestration: critical legal issues, Tyndall Centre

Working Paper 45

• Shackley, S., McLachlan, C. and Gough, C. (2004) The Public Perceptions of Carbon Capture and Storage, Tyndall

Centre Working Paper 44 • Anderson, D. and Winne, S. (2003)

Innovation and Threshold Effects in Technology Responses to Climate Change, Tyndall Centre Working Paper 43

• Kim, J. (2003) Sustainable Development and the CDM: A South

African Case Study, Tyndall Centre Working Paper 42

• Watson, J. (2003), UK Electricity Scenarios for 2050, Tyndall Centre Working Paper 41

• Klein, R.J.T., Lisa Schipper, E. and Dessai, S. (2003), Integrating

mitigation and adaptation into climate and development policy: three

research questions, Tyndall Centre Working Paper 40

• Tompkins, E. and Adger, W.N. (2003). Defining response capacity to enhance climate change policy, Tyndall

Centre Working Paper 39 • Brooks, N. (2003). Vulnerability,

risk and adaptation: a conceptual

framework, Tyndall Centre Working Paper

38 • Ingham, A. and Ulph, A. (2003)

Uncertainty, Irreversibility, Precaution and the Social Cost of Carbon, Tyndall Centre Working Paper 37

• Kröger, K. Fergusson, M. and Skinner, I. (2003). Critical Issues in

Decarbonising Transport: The Role of Technologies, Tyndall Centre Working Paper 36

• Tompkins E. L and Hurlston, L. (2003). Report to the Cayman Islands’

Government. Adaptation lessons learned from responding to tropical cyclones by the Cayman Islands’

Government, 1988 – 2002, Tyndall Centre Working Paper 35

• Dessai, S., Hulme, M (2003). Does climate policy need probabilities?, Tyndall Centre Working Paper 34

• Pridmore, A., Bristow, A.L., May, A. D. and Tight, M.R. (2003). Climate

Change, Impacts, Future Scenarios and the Role of Transport, Tyndall Centre Working Paper 33

• Xueguang Wu, Jenkins, N. and

Strbac, G. (2003). Integrating Renewables and CHP into the UK Electricity System: Investigation of the

impact of network faults on the stability of large offshore wind farms, Tyndall Centre Working Paper 32

• Turnpenny, J., Haxeltine A. and

O’Riordan, T. (2003). A scoping study of UK user needs for managing climate futures. Part 1 of the pilot-phase

interactive integrated assessment process (Aurion Project), Tyndall Centre Working Paper 31

• Hulme, M. (2003). Abrupt climate change: can society cope?, Tyndall


• Brown, K. and Corbera, E. (2003). A Multi-Criteria Assessment Framework for Carbon-Mitigation Projects: Putting

“development” in the centre of decision-making, Tyndall Centre Working Paper 29

• Dessai, S., Adger, W.N., Hulme, M., Köhler, J.H., Turnpenny, J. and Warren, R.

(2003). Defining and experiencing dangerous climate change, Tyndall Centre Working Paper 28

• Tompkins, E.L. and Adger, W.N. (2003). Building resilience to climate

change through adaptive management of natural resources, Tyndall Centre Working Paper 27

• Brooks, N. and Adger W.N. (2003). Country level risk measures of climate-

related natural disasters and implications for adaptation to climate change, Tyndall Centre Working Paper 26

• Xueguang Wu, Mutale, J., Jenkins, N. and Strbac, G. (2003). An investigation

of Network Splitting for Fault Level Reduction, Tyndall Centre Working Paper 25

• Xueguang Wu, Jenkins, N. and Strbac, G. (2002). Impact of Integrating

Renewables and CHP into the UK Transmission Network, Tyndall Centre Working Paper 24

• Paavola, J. and Adger, W.N. (2002). Justice and adaptation to climate

change, Tyndall Centre Working Paper 23

• Watson, W.J., Hertin, J., Randall, T., Gough, C. (2002). Renewable Energy and Combined Heat and Power

Resources in the UK, Tyndall Centre Working Paper 22

• Watson, W. J. (2002). Renewables and CHP Deployment in the UK to 2020, Tyndall Centre Working Paper 21

• Turnpenny, J. (2002). Reviewing

organisational use of scenarios: Case study - evaluating UK energy policy options, Tyndall Centre Working Paper 20

• Pridmore, A. and Bristow, A., (2002). The role of hydrogen in powering road

transport, Tyndall Centre Working Paper 19

• Watson, J. (2002). The development of large technical systems: implications for hydrogen,

Tyndall Centre Working Paper 18 • Dutton, G., (2002). Hydrogen

Energy Technology, Tyndall Centre Working Paper 17

• Adger, W.N., Huq, S., Brown, K., Conway, D. and Hulme, M. (2002). Adaptation to climate change: Setting

the Agenda for Development Policy and Research, Tyndall Centre Working Paper 16

• Köhler, J.H., (2002). Long run technical change in an energy-

environment-economy (E3) model for an IA system: A model of Kondratiev waves, Tyndall Centre Working Paper 15

• Shackley, S. and Gough, C., (2002). The Use of Integrated Assessment: An

Institutional Analysis Perspective, Tyndall Centre Working Paper 14

• Dewick, P., Green K., Miozzo, M., (2002). Technological Change, Industry Structure and the Environment, Tyndall


• Dessai, S., (2001). The climate regime from The Hague to Marrakech: Saving or sinking the Kyoto Protocol?,

Tyndall Centre Working Paper 12 • Barker, T. (2001). Representing

the Integrated Assessment of Climate Change, Adaptation and Mitigation, Tyndall Centre Working Paper 11

• Gough, C., Taylor, I. and Shackley, S.

(2001). Burying Carbon under the Sea: An Initial Exploration of Public Opinions, Tyndall Centre Working Paper

10 • Barnett, J. and Adger, W. N. (2001).

Climate Dangers and Atoll Countries, Tyndall Centre Working Paper 9

• Adger, W. N. (2001). Social Capital and Climate Change, Tyndall Centre Working Paper 8

• Barnett, J. (2001). Security and Climate Change, Tyndall Centre Working Paper 7

• Goodess, C.M., Hulme, M. and Osborn, T. (2001). The identification and

evaluation of suitable scenario development methods for the estimation of future probabilities of

extreme weather events, Tyndall Centre Working Paper 6

• Barnett, J. (2001). The issue of

'Adverse Effects and the Impacts of Response Measures' in the UNFCCC, Tyndall Centre Working Paper 5

• Barker, T. and Ekins, P. (2001). How High are the Costs of Kyoto for the US

Economy?, Tyndall Centre Working Paper 4

• Berkhout, F, Hertin, J. and Jordan, A. J. (2001). Socio-economic futures in climate change impact assessment:

using scenarios as 'learning machines', Tyndall Centre Working Paper 3

• Hulme, M. (2001). Integrated Assessment Models, Tyndall Centre Working Paper 2

• Mitchell, T. and Hulme, M. (2000). A Country-by-Country Analysis of Past

and Future Warming Rates, Tyndall Centre Working Paper 1

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