FIGURE 1.1 Yellow arrows track what summers are projected to feel like under a lower emissions scenario, while red arrows track projections for a higher emissions scenario. By late this century, residents of New Hampshire would experience a summer climate more like what occurs today in North Carolina. SOURCE: Frumhoff et al. (2007).

FIGURE 1.1 Yellow arrows track what summers are projected to feel like under a lower emissions scenario, while red arrows track projections for a higher emissions scenario. By late this century, residents of New Hampshire would experience a summer climate more like what occurs today in North Carolina. SOURCE: Frumhoff et al. (2007).

by human activities, and poses significant risks for—and in many cases is already affecting—a broad range of human and natural systems.” This is consistent with the analyses of the Intergovernmental Panel on Climate Change (IPCC, 2007b), which found that the global climate is warming, that this warming is very likely due to greenhouse gases from human activity, and that unless we reduce GHG emissions, the climate will warm by 2°F to 11.5°F (1.1°C to 6.4°C) by the end of the century and will have serious impacts on ecosystems, water resources, low latitude agriculture, coasts, ocean acidification, and increased risks of abrupt or irreversible change (Figure 1.1). The IPCC also recommends an iterative risk management approach1 that includes adaptation and emissions reduction strategies and that takes into account damages, co-benefits, sustainability, equity, and attitudes toward risk (IPCC, 2007b).


New research and data have confirmed and updated the trends and analyses of the IPCC and have suggested further reasons for concern. Climate data analyses show that the earth has continued to warm, sea ice and glaciers are shrinking, and regional

1

An iterative risk management framework defines risk as the impact of some adverse event multiplied by the probability of its occurrence (see IPCC, 2007b).



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