The Regional Impacts of Climate Change

	Other reports in this collection

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Differentiated impacts can occur across North America. As this assessment notes, particular areas and sectors within North America are projected to experience negative impacts, whereas other areas and sectors could benefit from the projected changes. Similarly, because of differences in adaptive capacity within North America, different areas and sectors will be better able to respond to climate change.

Climate change is a dynamic process that will occur over time. Although most of the literature on impacts, including the analysis in this assessment, has focused on a 2xCO₂ world, it is reasonable to expect that some of the kinds of impacts that have been discussed would begin to manifest themselves before atmospheric concentrations of CO₂ doubled. It also is important to recognize that 2xCO₂ is not a magic concentration; it is likely that, unless action is taken, we will pass 2xCO₂ on our way to even higher concentrations. It is not unreasonable to suggest that at these higher levels the negative and beneficial impacts (e.g., the benefits of CO₂ fertilization effects on vegetation) could be significantly different, even a nonfactor, in a 4xCO₂ world.

Many of the changes in climate that currently are being observed are consistent with the changes one would expect with greenhouse gas-induced climate change (IPCC 1996, WG I, Summary for Policymakers).

Many of the actions that might be taken today to address existing stresses might also help reduce vulnerability to potential climate change and variability. Options include, but are not limited to, actions such as the following:

• Improve management of water infrastructure, pricing policies, and demand-side management of supply to support the competing needs of domestic water supply, agriculture, industrial cooling, hydropower, navigation, and fisheries and habitat.
• Introduce accommodating adaptation options in the transportation sector, as the industry copes with other significant changes, through new technologies, markets, and products.
• Introduce effective land-use regulations that also help reduce vulnerabilities and direct population shifts away from vulnerable locations such as floodplains, steep hillsides, and low-lying coastlines.

Failure to consider climate change when making long-range decisions to manage stress response in any sector could increase the risk of taking actions that would prove ineffective or even counterproductive in the long run. Examples where consideration of climate change could prove prudent are:

• Actions taken currently that would reduce weather-related deaths associated with heat waves in urban areas also could reduce vulnerability to potential climate change that might increase the frequency and intensity of heat waves (IPCC 1996, WG I, Summary for Policymakers).
• Introducing sustainable water-supply management concepts today, whether to deal with shortages or excesses of water, could reduce vulnerability to potential climate change.

The concept of "effective" adaptation by any given sector assumes that those affected have the ability and the foresight to discern changing climate trends from short-term weather patterns and to make strategic anticipatory adaptations accordingly. It is not clear that, if changes in climate and weather patterns or variables fall outside people's experience, they will be able to adapt effectively in the near term. If they are not able, there may be short-term transitional impacts on those individuals and decision makers (e.g., resource managers, farmers, fishermen, loggers, or ranchers).