Recent Accomplishments in Global Change Process Research

• Experimental research on the uptake of carbon by mid-latitude forests suggests that these forests may be a greater sink for carbon than previously thought.

• The residence time of methane in the atmosphere has been found to be significantly larger than previous estimates. Recognition of the role of methane as an important greenhouse gas has been increased.

• Research on the radiative effects of sulfate particles, formed in the lower atmosphere from emissions of sulfur dioxide, could be at least temporarily counterbalancing warming due to increasing concentrations of greenhouse gases.

• Studies on past climate from ice core data continue to indicate that abrupt climatic shifts occurred frequently in these regions over time scales on the order of decades or less over the last few million years.