Paleoclimate studies extend records of climate beyond the time period for which we have instrumental measurements. Such research not only answers questions about what Earth was like in the past, but also provides context for the climate changes that we are experiencing today and informs our understanding of how climate is likely to change in the future. In 2013, an international team of researchers published the most comprehensive reconstruction of past temperature changes ever generated at the continental scale.
...Highlights
Since 1989, the U.S. Global Change Research Program (USGCRP) has submitted annual reports to Congress called Our Changing Planet. The reports describe the status of USGCRP research activities, provide progress updates, and document recent accomplishments
In particular, Our Changing Planet highlights progress and accomplishments in interagency activities. These highlights represent the broad spectrum of USGCRP activities that extend from Earth system observations, modeling, and fundamental research through synthesis and assessment, decision support, education, and public engagement.

Pollution from the combustion of fossil fuels and wood has contributed to climate change in complex ways, with some pollutants causing cooling and others causing warming, accompanied by effects on patterns of atmospheric circulation and precipitation. To better understand these complex relationships, the Atmospheric Chemistry Climate Model Intercomparison Project, part of the international 5th-phase Coupled Model Intercomparison Project (CMIP5), conducted a series of pollution-focused modeling experiments to reveal spatial patterns, sectoral influences,




