Adapting to Climate Change: “Some thoughts on Adaptation” SAGES 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

Or living in a 3oC or a 4oC world

Future global change – great uncertainty

Predicted Changes in precipitation

Heat waves such as 2003 expected to become more common

2007 flooding: A sign of things to come?

Modelling Global Climate Vertical exchange between layers of momentum, heat and moisture 15° W Horizontal exchange between columns of momentum, heat and moisture 60° N 3.75° 2.5° Vertical exchange between layers of momentum, heat and salts by diffusion, convection and upwelling 11.25° E 47.5° N Vertical exchange between layers by diffusion and advection Orography, vegetation and surface characteristics included at surface on each grid box

Model resolution increasing with time.

Parameterized Processes 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. Slingo From Kevin E. Trenberth, NCAR

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.

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.

Changes Global-Scale Precipitation European 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.

Cold Season Precip N-Euro inconsistent for both ensembles. ALL better. N-Euro inconsistent for both ensembles. ALL better. Med Natural inconsistent Thick lines: Obs Symbols: model results Dotted lines: Ctl uncert (5-95%). Red:Med Black:N-Euro

Climate “Impacts” Ecological/Biological impacts CO2, CH4, surface properties Agriculture->Food Production Flooding Heat Waves Tourism Damage to infrastructure Loss of implicit knowledge Storminess changes “Impacts”

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.

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???

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.

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.)

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??

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.