The Intergovernmental Panel on Climate Change released in 2007 a series of reports expressing the current state of knowledge about climate change. These are the most definitive reports from the world's leading scientists.
U.S. Government Reports
Global Climate Change Impacts in the United States, released in 2009 by the U.S. Global Change Research Program -- by far the best overall reports on climate change in the United States.
The Effects of Climate Change on Agriculture, Land Resources, Water Resources, and Biodiversity released in May 2008 by the U.S. Climate Change Science Program.
Also, borrowing heavily from the above report and the IPCC's 2007 reports, the U.S. government also released in May 2008 Scientific Assessment of the Effects of Global Change on the United States, a national assessment required by law.
The National Academy of Sciences in 2001 released Climate Change Science: An Analysis of Some Key Questions.
In 2007, the National Academy of Sciences released Colorado River Basin Water Management: Evaluating and Adjusting to Hydroclimatic Variability, dealing in part with climate change in the Colorado River basin.
Some Key Articles
J. A. Logan and J. A. Powell. Ecological consequences of climate change altered forest insect disturbance regimes. In F. H. Wagner (ed.), Climate change in western North America: evidence and environmental effects. (In press).
Brad Udall and Gary Bates, Climatic and Hydrologic Trends in the Western U.S.: A Review of Recent Peer-Reviewed Research (2007).
A. L. Westerling and others, Warming and Earlier Spring Increase Western U.S. Forest Wildfire Activity (2006).
Philip W. Mote and others, Declining Mountain Snowpack in Western North America (2005).
Katharine Hayhoe and others, Emissions Pathways, Climate Change, and Impacts on California, in Proceedings of the National Academy of Sciences, August 2004.