Atmospheric Aerosol Properties and Climate Impacts

A detailed look at global distributions and properties of airborne particles known as "aerosols." The report examines the various ways in which aerosols influence climate, and the uncertainties in our ability to observe and measure these particles' impact on the climate system.

Thresholds of Climate Change in Ecosystems

An assessment of the potential for abrupt state changes or regime shifts in ecosystems in response to climate change.  Better understanding of sudden changes to ecosystems, and the goods and services they provide, is extremely important if natural resource managers are to succeed in developing adaptation strategies.

Past Climate Variability and Change in the Arctic and at High Latitudes

Over the past 30 years, average temperatures in the Arctic have increased at almost twice the rate of the planet as a whole. Such temperature changes have been accompanied by shrinking sea ice, melting ice and permafrost on land, and widespread impacts to land and ocean ecosystems.

Abrupt Climate Change

An assessment of abrupt climate change events where key aspects of Earth's climate system change faster than the responsible forcings would suggest and/or faster than society can respond. This report examines four types of abrupt change in Earth's past that were so rapid and so large in their impact that if they were to recur today they would pose clear risks to society in terms of our ability to adapt.

Climate Projections Based on Emissions Scenarios for Long-Lived and Short-Lived Radiatively Active Gases and Aerosols

An assessment of the effects of short-lived gases and particles in the atmosphere. They can significantly change regional surface temperatures. By the year 2100 short-lived gases and particles may account for as much as 40 percent of the warming over the continental U.S. in summertime.

Weather and Climate Extremes in a Changing Climate

An assessment in the state of knowledge concerning changes in weather and climate extremes in North America and U.S. territories. Changes in extreme weather and climate events have significant impacts and are among the most serious challenges to society in coping with a changing climate.

Arctic Climate Impact Assessment

An international project of the Arctic Council and the International Arctic Science Committee, the Arctic Climate Impact Assessment evaluates and synthesizes knowledge on climate variability, climate change, and increased ultraviolet radiation and their consequences for the Arctic region.