Projected changes in climate and physical processes

In Chapter 3, we examined how climate has changed in the Mid-Atlantic region during the past century. This chapter examines how climate is expected to change during the 21st century, including changes in extreme weather events and other climaterelated processes. General circulation models, also called global climate models (GCMs), are used to project future change at coarse spatial scales and then downscaled in order to be relevant at scales where land management decisions are made. These downscaled data can then be incorporated into forest species distribution models and process models (results are presented in Chapter 5). Chapter 2 more fully describes the models, data sources, and methods used to generate these downscaled projections, as well as the inherent uncertainty in making long-term projections. In Chapter 4, we focus on two climate scenarios for the assessment area, chosen to bracket a range of plausible changes in average annual and seasonal temperatures and precipitation totals. We note, however, that the two models selected here do not necessarily represent the bracketed range in terms of other metrics such as daily maximums and minimums, or extremes. Therefore, readers should exercise caution when interpreting future trends. Information related to future weather extremes and physical processes is drawn from published research.