On June 23, 2005, Reps. Joe Barton (R-Texas), chairman of the House Committee on Energy and Commerce, and Ed Whitfield (R-Kentucky) wrote to University of Arizona professor Malcolm Hughes and his colleagues Michael Mann (University of Virginia) and Raymond Bradley (University of Massachusetts), requesting extensive original data and grants information. Rep. Barton also wrote to the National Science Foundation, asking for a list of all grants and awards the NSF had made in climatology and paleoclimatology in the past decade and for information about the roles of individuals in the grant-review process. The three scientists had presented results ("Global-Scale Temperature Patterns and Climate Forcing Over the Past Six Centuries," Nature, 1998, and "Northern Hemisphere Temperatures During the Past Millennium: Inferences, Uncertainties, and Limitations," Geophys. Res. Lett., 1999) suggesting that temperatures in the Northern hemisphere had been warmer in the 1990s than in the preceding 1000 years. Their results, along with those of many other scientists, were used by the United Nations in 2001 to conclude that emissions of "greenhouse gases" have caused a recent warming of the earth. Dr. Hughes and his colleagues made available on the website of Nature (www.nature.com) in July 2004 the entire dataset along with extended explanations of algorithms used in the publications in question, and the data from "proxy records of climate" have been freely available for several years. In December 2003, the NSF declared in writing that the three scientists had fully complied with NSF policies regarding public access to data generated in federally-funded projects.