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International Seminar on the Climate System and Climate

Change

Lecture 1

• Setting the scene: the Intergovernmental Panel on Climate Change (IPCC) and the Fifth Assessment Report (AR5)

Lecture 2• Zooming in: Cities and Climate Change Adaptation in AR5

Lecture 3

• On the ground: Climate Change Response Planning in Durban, South Africa

Lecture 4

• Where to next?: Local resilience, Sixth Assessment Cycle (AR6) and the emerging international cities and climate change science research agenda

Lecture 1

•Setting the scene: the IPCC and AR5

The role of the IPCC ➜ The Intergovernmental Panel on Climate Change (IPCC)

was established by World Meteorological Organization (WMO) and United Nations Environmental Programme (UNEP) in 1988.

➜ Its role is to to assess scientific, technical, and socioeconomic information* that is relevant in understanding human-induced climate change and provide policy-makers with an objective source of information about • causes of climate change, • potential environmental and socio-economic impacts,• possible response options (adaptation and mitigation).

* NB does not do research. Policy relevant but not policy prescriptive.

IPCC Reports

• UN body

• Intergovernmental Panel

(195 member States)

• 3 WGs + TFI co-ordinate and oversee assessment process

• International scientists and experts

Governance Structure: Policy/Science Interface

Achievements: The Assessment Reports

IPCC and the Paris Agreement 2015

The Conference of the Parties (CoP):

“21. Invites the Intergovernmental Panel on Climate Change to provide a special report in 2018 on the impacts of climate warming of 1.5 ºC above pre-industrial levels and related global greenhouse gas emissions pathways”

(In response to Article 2’s intention to hold: “the increase in the global average temperature to well below 2°C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5°C above pre-industrial levels”)

IPCC and the Paris Agreement 2015 (contd.)

“1. The Conference of the Parties serving as the meeting of the Parties to the Paris Agreement shall periodically take stock of the implementation of the Agreement to assess the collective progress towards achieving the purpose of this Agreement and its long-term goals referred to as the “global stocktake”)…

2. The Conference of the Parties serving as the meeting of the Parties to the Paris Agreement shall undertake its first global stocktake in 2023 and every five years thereafter…

IPCC and the Paris Agreement 2015 (cont.)

The CoP:“99. Requests the Ad Hoc Working Group on the Paris Agreement to identify the sources of input for the global stocktake referred to in Article 14 of the Agreement and to report to the Conference of the Parties, with a view to the Conference of the Parties making a recommendation to the Conference of the Parties serving as the meeting of the Parties to the Paris Agreement for consideration and adoption at its first session, including, but not limited to:(b) The latest reports of the Intergovernmental Panel on Climate Change”

The CoP:“100. Also requests the Subsidiary Body for Scientific and Technological A d v i c e t o p r o v i d e a d v i c e o n h o w t h e a s s e s s m e n t s o f t h e Intergovernmental Panel on Climate Change can inform the global stocktake of the implementation of the Agreement pursuant to its Article 14 of the Agreement and to report on this matter to the Ad Hoc Working Group on the Paris Agreement at its second session”

IPCC AR5 Synthesis Report

So what were the key findings of AR5?


Key messages from IPCC AR5• Human influence on the climate system is clear

• Continued GHG emissions will increase the likelihood of severe, pervasive and irreversible impacts for people and ecosystems

• While climate change is a threat to sustainable development, there are many opportunities to integrate mitigation, adaptation, and the pursuit of other societal objectives

• Humanity has the means to limit climate change and build a more sustainable and resilient future


What changes have we already been

detected/observed?

(Lüthi et al.,2008, NOAA)

40%2014

The concentrations of CO2 have increased by 40% since

preindustrial times to levels unprecedented in at least the

last 800 000 years.

1000 years before present

CO

2 Con

cent

ratio

ns (p

pm)

Atmospheric concentrations of CO2


Sources of emissionsEnergy production remains the primary driver of GHG emissions

35%24% 21% 14% 6.4%

2010 GHG emissions

(CO2, CH4, N2O, HFCs, PFCs, SF6, NF3)

Energy Sector

Agriculture, forests and

other land uses

Industry TransportBuilding Sector

AR5 WGIII SPM

Figure SPM.1a Surface TemperatureObserved globally averaged combined land and ocean surface temperature anomaly 1850-2012

All Figures © IPCC 2013

Last 3 decades

hottest on record.

Since 1950, extreme hot days and heavy precipitation have become more common

17

There is evidence that anthropogenic influences, including increasing atmospheric greenhouse gas concentrations have changed the

frequency of these extreme events.


Oceanic uptake of CO2 has resulted in acidification of the ocean

The pH of ocean surface water has decreased by 0.1 (high confidence), corresponding to a 26% of increase in acidity, measured as hydrogen ion concentration

AR5 SYR; AR5 WG1 SPM.4b


Impacts are already underway

• Tropics to the poles• On all continents and in the ocean• Affecting rich and poor countries (but the

poor are more vulnerable everywhere)

AR5 WGII SPM


What is projected to happen in the future?

Representative Concentration Pathways (RCP) Scenarios: Atmospheric CO2 concentration

AR5, chapter 12. WGI

Radiative forcing values (heating potential) in the year 2100 relative to pre-industrial values

Three stabilisation scenarios: RCP 2.6 to 6One Business-as-usual scenario: RCP 8.5

Only the lowest (RCP2.6) scenario maintains the global surface temperature increase at

less than 2°C above the pre-industrial level with at least 66% probability

(IPC

C 2

013,

Fig

. SPM

.7a)

IPC

C 2

013,

TFE

.2, F

ig. 2

1901-2010:19 cm

RCP8.5: 52 to 98 cm by

2100

Sea Level


Potential Impacts of Climate Change

AR5 WGII SPM

Food and water shortages

Increased poverty

Increased displacement of people

Coastal flooding

Biodiversity loss Urban areas at risk

WITH CONTINUED HIGH EMISSIONS

INCREASE

RISKS OF CLIMATE CHANGE

“Burning Embers Diagram”

Fig. SPM.10

The carbon budget was a new addition in AR5 – based on almost linear relationship between cumulative CO2 emissions and

temperature increase.

© IP

CC

201

3


The window for action is rapidly closing65% of the carbon budget compatible with a 2°C goal is already usedNB: this is with a probability greater than 66% of staying below 2°C

Amount Used1870-2011:

1900GtCO2

Amount Remaining:

1000GtCO2

Total Carbon Budget:

2900GtCO2

AR5 WGI SPMNB: Emissions in 2011: 38 GtCO2/yr

Working Group III contribution to the IPCC Fifth Assessment Report

Can temperature rise still be kept below 1.5 or 2°C (over the 21st century) compared to pre-industrial ? • Many scenario studies confirm that it is technically and economically feasible to keep the warming below 2°C, with more than 66% probability (“likely chance”). This would imply limiting atmospheric concentrations to 450 ppm CO2-eq by 2100.

• Such scenarios (i.e. an above 66% chance of staying below 2°C) imply reducing global GHG emissions by 40 to 70% compared to 2010 by mid-century, and reaching zero or negative emissions by 2100. (Do the models represent reality?)

In order to achieve the long-term temperature goal set out in Article 2, Parties aim to reach global peaking of greenhouse gas emissions as soon as possible, recognizing that peaking will take longer for developing country Parties, and to undertake rapid reductions thereafter in accordance with best available science, so as to achieve a balance between anthropogenic emissions by sources and removals by sinks of greenhouse gases in the second half of this century, on the basis of equity, and in the context of sustainable development and efforts to eradicate poverty.

Paris Agreement: Article 4


GHG emissions growth between 2000 and 2010 has been larger than in the previous three decades.

33


More than half of the cumulative anthropogenic emissions of CO2 between 1750 and 2010 occurred in the last 40 years.

35

IPCC WGIII AR5 based on Figure 5.3


Most of the recent GHG emission growth has been driven by growth in economic activitiy.

36


The long-standing trend of gradual decarbonisation of energy has reversed recently.

37


Delaying mitigation increases the difficulty and narrows the options for limiting warming to 2°C.

39

What we do in the short term matters: if we take immediate

action i.e. that GHG emissions do not grow beyond today‘s level



40

Emission reductions between 2030 and 2050 of about 3% per

year globally



41

Double the share of

low carbon energy


Delaying mitigation is estimated to increase the difficulty and narrow the options for limiting warming to 2°C.

42

Immediate action

Delayed mitigation



43

Emission reductions of 6% per year



44

Triple the share of low

carbon energy –

more costly


Co-benefits of climate change mitigation for human health could be large and provide short-term incentives for climate policies.

46

Based on Figures SPM.6 and 12.23


Mitigation Measures

AR5 WGIII SPM

Time, 2011

• Substantial reductions in emissions would require large changes in investment patterns e.g., from 2010 to 2029, in billions US dollars/year: (mean numbers rounded, IPCC AR5 WGIII Fig SPM 9)

• energy efficiency: +330 • renewables: + 90• power plants w/ Carbon Capture and Storage (CCS): + 40• nuclear: + 40• power plants w/o CCS: - 60• fossil fuel extraction: - 120


The choices humanity makes will create different outcomes (and affect prospects for effective adaptation)

With substantial mitigation

Without additional mitigation

Change in average surface temperature (1986–2005 to 2081–2100)AR5 WGI SPM

Thank you

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