To estimate the climate impact of planting forests in different parts of the United States, ecologist Christopher Williams at Clark University in Worcester, Massachusetts, is combining global satellite data collected over more than a decade with carbon-sequestration figures based on data from the US Forest Service. He has found in preliminary work that adding trees to the US west coast and to regions east of the Mississippi River makes sense, climatically speaking. But albedo changes make forest planting in the Rockies and the southwestern United States a bad deal for the climate in most cases, because the conifers that thrive in those regions are dark and absorb more sunlight than do underlying soils or snow. He hopes to turn this research into a standardized methodology that forest managers can use to assess a project’s climate impact.
Getting planners to adopt such methods could prove challenging, however. Williams has found that some resist considering albedo effects, including representatives of companies hoping to sell carbon credits for forest projects. “Even other scientists sometimes have disbelief in the magnitude of the albedo effect, or even its existence,” he says.