This report presents a review of economic studies for the United States and relates them to predicted impacts of climate change. The summary findings are organized by region and identify the key sectors likely affected by climate change, the main impacts to be expected, as well as estimates of costs. The report builds on the 2000 Global Change Research Program National Assessment, using additional regional and local studies, as well as new calculations derived from federal, state and industry data sources. From this review and quantification, five key lessons emerge:

1. Economic impacts of climate change will occurthroughout the country
2. Economic impacts will be unevenly distributedacross regions and within the economy andsociety.
3. Negative climate impacts will outweighbenefits for most sectors that provide essentialgoods and services to society.
4. Climate change impacts will place immensestrains on public sector budgets.
5. Secondary effects of climate impacts caninclude higher prices, reduced income and joblosses.

This paper addresses five issues encountered when estimating secondary benefits in regional project analysis; (a) the correction for opportunity cost of factors used, (b) the treatment of mobile factors, (c) the effect of economies of size, (d) the role of forward linkages, and (e) the role of spatial structure of economic regions. The first four are reasons that only a small part, if any, of regional impacts can be treated as regional net benefits. The fifth is a reason that, when secondary benefits or damages do exist, their correct estimation can depend on the spatial structure of the affected areas.