CESDSAGES Scottish Alliance for Geoscience, Environment &

Society

Adapting to Climate Change:

Or living in a 2oC world

“Some thoughts on Adaptation” Simon Tett; University of Edinburgh

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Or living in a 3oC or a 4oC world

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Future global change – great uncertainty

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Predicted Changes in precipitation

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Heat waves such as 2003 expected to become more

common

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2007 flooding: A sign of things to come?

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Vertical exchange between layersof momentum, heat and moisture

Horizontal exchangebetween columnsof momentum, heat and moisture

Vertical exchangebetween layersof momentum, heat and saltsby diffusion, convectionand upwelling Orography, vegetation and surface characteristics

included at surface on each grid box

Vertical exchange between layersby diffusion and advection

Modelling Global Climate

15° W60° N

3.75°

2.5°

11.25° E47.5° N

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Model resolution increasing with time.

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Parameterized Processes

Slingo From Kevin E. Trenberth, NCAR

Model’s do not have enough resolution to resolve these processes. So they are represented in terms of the large-scale flow (what gets simulated). Many of these processes act at scales of 1-10km.

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Climate Model development

• Global models resolve scales of about 100km.• Regional models (high resolution in specific

regions) give resolution of 10-25km.• UKCP09 for UK. Uncertainty estimates for range

of possible futures.• Climate Models continue to be developed –

need continual comparison with observations.• Climate Models continue to be uncertain largely

as a result of uncertainty in parameterisations.

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Climate change science

– To what extent do observations of current climate, climate variability & change constrain possible future climate change?

– Climate is weather we expect. Includes stochastic and forced components

– Relative importance depends on variable and scale.– Global-mean temperature – strong forcing relative to

stochastic – Rainfall in Edinburgh in mid-November – very strong

stochastic forcing vs forced.

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Changes

Global-Scale Precipitation• Wet areas get wetter; dry drier • Less days on which it rains but more intense rain

when it does. (rain gets more extreme)

– European precipitation• Models predict increase in rainfall in winter• Med region (up to S England) drier in summer.

– Storm tracks move polewards.

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Cold Season Precip

Thick lines: Obs Symbols: model results

Dotted lines: Ctl uncert (5-95%). Red:Med Black:N-Euro

N-Euro inconsistent for both ensembles. ALL better.

N-Euro inconsistent for both ensembles. ALL better. Med Natural inconsistent

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ClimateEcological/Biological impacts

CO2, CH4, surface properties

“Impacts”

•Agriculture->Food Production•Flooding•Heat Waves•Tourism •Damage to infrastructure•Loss of implicit knowledge•Storminess changes

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Modelling Impacts

• Is modelling impacts helpful?• “Impact” models generally more empirical than

climate models – no helpful Physical laws to guide us.

• For example Hydrological models are mainly empirical – leading to issue of ungauged catchments

• So are uncertain (more than climate models) and probably suffer more from unknown unknowns..

• So climate change is uncertain, impacts are uncertain.

• Decision making under (considerable) uncertainty.

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Temperature Impacts

• Heat waves & reduction in cold winters– Less deaths in winter (which we could already have adapted to

by better insulation) [Does this say something about social adaptation??]

– More (peaky??) deaths in summer – research suggests the impact is very dependant on all kinds of social factors.

– Engineering solution – air conditioners for all.– Social solution – good support networks. “Shelters”.

• For Scotland don’t see heat waves as major issue by 2050.

• So might be net gain for Scotland – warmer winters reducing death and summer not hot enough to push temperatures to dangerous levels.

• European response – more visitors to Scotland in summer???

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Rainfall

• Sufficient water resources? How much to spend to move/store water? Demand management. Population management! (move people away from SE England).

• “Physical Engineering” vs “Social Engineering” • How to determine effectiveness of different

strategies?• Long timescales – for impact and for

infrastructure• Impact of precipitation changes on infrastructure

and landscape.

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Mitigation of impact

• What to adapt to?• Target is 2K warming. No chance!• 3K, 4K,,,, -- but what are “impacts” of such global mean

changes?• Sea level rise as Greenland melts. Heatwaves, changes

in extreme precipitation and unknown unknowns..• Implies costs will be large – we and our descendants will

be worse of.• Community/individual vs Nation/expert.• Current policy.

– Should poor communities in West Glasgow be expected to develop their own response to climate change?

– What about rich communities in South Edinburgh.)

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Mitigation of impact

• Resources limited – want to maximise benefit• Role of social science here. What approaches

work best.• Evolutionary strategy – adapt as we go along.

Events dear boy. Tricky in a chaotic climate system – learn wrong lessons from single events.

• Is rational decision making possible? Countries/Economies that best mitigate impacts climate change might do best. [What is the morality of this thought.]

• Geo-engineer??

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Homecoming… (Or what should Scotland do?)

• Current strategy is Rural focused. Probably sensible for reducing GHG emissions.

• But for adaptation…. Scotland an urban society. Need to focus on mitigating impacts of climate change on urban areas. Alas centre for Risk & Uncertainty focused on rural – landuse….– Recognize that different communities have different capacities.– Some can (partially) own strategy. All will need some help. – What technical and social strategies work well?– What don’t.– Combination of Physical research – what should we mitigate.

What physical engineering approaches might work.– And Social research – what works with society. – Example thought. Flooding. Build bigger/better flood defences vs

change in management of land around flood plain to reduce speed of runoff.