Climate adaptation
Chair: André de Palma (Cergy-Paris University)
Most research on climate change has focused on mitigation by reducing greenhouse gas (GHG) emissions and capturing CO2 already in the atmosphere. By comparison, relatively little attention has been devoted to adaptation. One reason is that clear performance measures for adaptation are not as tangible as measures for mitigation such as vehicle fuel efficiency standards. Another, overriding, reason is that the great uncertainties surrounding climate change make it difficult to plan and finance adaptation strategies – particularly at the regional and local level. Predictions of the rise in mean global surface temperature range widely. The trend in GHG emissions will depend on the rate of global economic growth, changes in technology, and efforts devoted to mitigation. In turn, these factors will be influenced by the rate at which climate-change effects become apparent, how they are expected to evolve in the future, and so on.
Uncertainty about climate effects increases as the geographical scale shrinks. The temperature scaler indicates that a 1°C average global warming results in a 2.2°C increase near the North Pole but only a 0.5°C increase in some more southern regions). The rate of sea level rise at a given location also has a wide confidence interval. Local changes to extreme water levels are more uncertain because of sensitivity to potential changes in the track of storms. Other effects such as changes in rainfall, and the frequency and intensity of storms, are uncertain even in sign. Feedback effects in climate can be positive or negative, rapid and catastrophic changes are becoming more common, and tipping points cannot be ruled out. The economic costs of climate change are very uncertain. There is uncertainty about the future level of emissions, its effects on climate, and the success of adaptation policies that mitigate the economic damage. At the high end, Bilal and Känzig (2024) estimate that even a modest 1°C increase in average global temperature for one year reduces world real GDP per capita with a peak reduction of 12% after about 6 years. Cruz & Rossi-Hansberg (2024) estimate the discounted GDP loss for a 2.2°C warming at 1% but count for this on successful adaptation policies with national and international migration and adaptation of economic activities. All these uncertainties increase the difficulty of planning and financing adaptation strategies. Adaptation to growing climate threats such as sea level rise, extreme storms, and heat waves can occur in various ways. Higher temperatures can be made more tolerable by air conditioning more intensively or using light colours for pavements and the roofs of buildings. Flood damage can be reduced by installing better pumps and drains, and leaving the ground floors of buildings empty. Protective structures such as seawalls can be built or reinforced. Buildings, roads, and other infrastructure can be relocated away from coastlines and flood plains. Crops can be relocated to places with more suitable temperatures, precipitation, and shade, and different crops perhaps planted in their place. Tourism can be redirected towards places that are safer and have better weather, and people can migrate to countries with more congenial climates. Insurance markets can adapt by offering new policies, adjusting existing policies, or even withdrawing coverage if risks become too high. The workshop on adaptation to climate change will address these and other considerations.
- David LACOSTE (ESPCI)
- Nathalie Picard (BETA, Unistra)
- andré de Palma ( CYU CERGY PARIS UNIVERSITE)