Arizona State University professor Nancy Grimm is one of the authors of a new and authoritative federal study assessing the current and anticipated domestic impacts of climate change. The report, "Global Climate Change Impacts in the United States," was released June 16 by the U.S. Office of Science and Technology Policy, which advises the President on the effects of science and technology on domestic and international affairs.

The main message in the report is that climate change is already having visible impacts in the United States, and, the choices that are made now will determine the severity of its impacts in the future.

The report compiles years of scientific research and takes into account new data not available during the preparation of previous large national and global assessments. It was produced by a consortium of experts from 13 U.S. government science agencies and from several major research institutes and universities, including Arizona State University.

"This report is a very thorough, sobering synthesis of what we now know about the impacts of climate change on all of us. In summarizing the latest and best science, it tells us that climate change is undeniably happening now, and that the choices we make - for reducing carbon dioxide emissions or adapting to the climate change that is 'locked in' - will have a large effect on our future," said Grimm, a faculty leader of Ecology, Evolution and Environmental Science in ASU's School of Life Sciences in the College of Liberal Arts and Sciences.

Grimm, who is the lead principal investigator and co-director of the Central Arizona-Phoenix Long-Term Ecological Research project (CAP LTER), also is an affiliate faculty member of ASU's School of Sustainability. Her research concerns the effects of human activity on nitrogen cycling and retention in deserts, cities and streams.

"The report is the first of its kind in 10 years, and we hope it will have an immediate and dramatic effect on climate-change policy at all levels in the U.S. We don't make policy recommendations but we present the best available science about climate change in a compelling and easy to understand way," said Grimm, who, as one of the members of the federal advisory committee authors team, contributed in particular to the report's chapters on water, society and the Southwest.

According to the authors, the study finds that Americans are already being affected by climate change through extreme weather, drought and wildfire trends and details how the nation's transportation, agriculture, health, water and energy sectors will be affected in the future. The study also finds that the current trend in the emission of greenhouse gas pollution is significantly above the worst-case scenario that this and other reports have considered.

"Rapid urbanization and projections of increasing drought represent almost a double-whammy for our region of the country," Grimm said. "People seem to want to live and build their cities precisely where the risk of impacts is greatest: along coasts and in the driest regions of the country.

"ASU's emphasis on urban sustainability, including our CAP LTER project and the Decision Center for a Desert City, among others, are taking highly appropriate research directions for responding to climate change. Working on this report was tremendously influential for me, since it confirms that our research can generate the kind of information that will help decision makers in Arizona and other dryland regions in the face of changing climate."

"This report is a game-changer," said Jane Lubchenco, under secretary of commerce for oceans and atmosphere and administrator of the National Oceanic and Atmospheric Administration (NOAA). "This report demonstrates and provides concrete information that climate change is happening now; in our own backyard.

A product of the interagency U.S. Global Change Research Program, the 190-page report, produced under NOAA's leadership, is available for download online at www.globalchange.gov/usimpacts.