Acknowledging the magnitude of predicted effects of global warming and adjusting to the consequences (rather than reducing the scale of climate change impacts); also adapting by minimizing the effects of climate change impacts.
In response to a growing understanding of adaptation as an important response to climate change, many countries have begun identifying, assessing, and adopting measures to adapt to climate change. It is recognized that these adaptations reduce vulnerability to current climate extremes and will help in coping with changes in future climate.
There is broad scientific agreement that even if action is taken at once to curb emissions of greenhouse gases, some warming of the Earth's climate is inevitable. Adaptive measures therefore require urgent consideration. Of particular concern are phenomena such as droughts, floods, cyclones, abnormal tides and storm surges, coastal erosion, outbreaks of cholera, malaria and other health problems exacerbated by climate change, and failure of food supplies.
This strategy features in the framework of Agenda 21 as formulated at UNCED (Rio de Janeiro, 1992), now coordinated by the United Nations Commission on Sustainable Development and implemented through national and local authorities.
Agenda 21 recommends cooperating with a view to adopting special measures to cope with and adapt to potential climate change and sea-level rise, including the development of globally accepted methodologies for coastal vulnerability assessment, modelling and response strategies particularly for priority areas, such as small islands and low-lying and critical coastal areas.
Typical adaptation strategies are building dykes to offset the effects of rising sea levels, developing drought-resistant plant strains, improving climate control in buildings, preparing farmers for changes in crops, and arranging for migrations from areas where heat, drought or flooding are already problematic or are likely to be so.
There are three basic means of coping with climate change: adaptation, climate engineering and abatement. Relying exclusively on adaptation policies is not a serious response to climate change. However, some degree of adaptation will probably be required; in a sense it is the job of other policy responses to climate change to minimize the degree of adaptation necessary. Climate engineering is probably too risky. This means that abatement measures must be pursued vigorously. The latter include domestic and international emissions taxes, the use of external offsets, and a tradable permit system, the latter appearing the most promising.
Adaptation includes actions such as increasing irrigation efficiency, breeding more drought-resistant crops, and developing buffer stocks of food. Scientists point out that adapting to climatic variability has a substantially greater effect of reducing impact than does mitigation. As an example, calculations show that reducing water demand by just 5% by 2020 has four times the effect of reducing emissions by 30%.
Adaptation strategies would probably benefit cold areas most and hot areas least. Since many of the world's poorest people already live in hot, dry regions, adaptation policies are unlikely to be attractive to the governments of developing countries. There is an added danger that some adaptations, such as the increased use of air conditioning in warm countries, would increase the rate or extent of climate change.
Climate change might be manageable in some industrialized countries, but what about Egypt, Bangladesh, Senegal or Thailand which stand to lose their most fertile coastal zones, whose agricultural sector share of GNP is as high or higher than 50%, and who lack the financial resources to replace this loss in food production by buying on the world markets (even if these markets can still supply)?