Written by Melanie Lenart, University of Arizona
While global climate models continue to improve, it remains challenging to downscale the models to the extent desired by foresters and other resource managers. As a result, managers are finding other creative ways to consider how the ongoing climate change is likely to affect the forests and other ecosystems in their care.
Best practices for downscaling global climate model (GCM) output call for avoiding scaling down to a resolution that is less than 1/12th of the area of the input model’s resolution (Bader et al. 2008). The highest-resolution GCMs have grid cells of roughly 24,000 square miles each (or 250 kilometers on a side, as modelers describe it). Thus, under best practices, a regional modeler could justify downscaling to about 2,000 square miles. Still, that resolution doesn’t necessarily bring it down to the scale of most national parks, much less a family-owned timber stand.
GCMs generally agree that temperature will increase in decades to come in response to ongoing emissions of heat-trapping greenhouse gases. But just how high the temperatures will rise, and exactly how this rise will affect precipitation levels, changes in seasonal snow melt, and other variables remains largely uncertain. While climate models are improving, some of the uncertainty relates to difficult-to-predict factors, such as whether society will choose to reduce its emissions of greenhouse gases, the complex role of clouds and pollution, and the extent to which forests will continue to absorb a large share of the greenhouse gas carbon dioxide released by the burning of fossil fuels and deforestation.
Given these challenges and the need to consider the system's potential sensitivity and adaptability to projected changes, resource managers are applying other approaches, including:
Related to Interpreting Climate Data for Land Management:
