were relatively stable for 900 years and then rose rapidly between 1900 and 2000, providing a fingerprint for human-caused climate change.20

After the release of the Third Assessment Report of the Intergovernmental Panel on Climate Change that cited this finding in 2001, it became a point of contention in debates over the reality and causes of global warming. Mann resisted when researchers skeptical of his work requested access to the underlying data and computer programs used in the reconstruction, and controversy ensued.21 Two Members of the U.S. House of Representatives issued a letter requesting a wide variety of information from each of the three co-authors of the paper, giving them 18 days to provide, among other things, a curriculum vitae with a list of all studies they authored on climate change and the specific sources of funding; a list of all financial support received from private, state and federal sources for climate-related work; the location of all underlying data archives related to such research and its specific availability; correspondence regarding requests for such data from other researchers, responses to such requests and the researchers’ reasons for their decisions, and in-depth responses to inquiries about their work on bristlecone pines and the Intergovernmental Panel on Climate Change.22 This request was viewed by some as intimidation.23 The National Research Council released a study in 2006 that examined the rapidly emerging field of multiproxy paleoclimate studies.24 The report ultimately affirmed some, but not all, of the key results of Mann’s work, while stating that “all research benefits from full and open access to published datasets and . . . a clear explanation of analytical methods is mandatory.” The report also points to the need for researchers, professional societies, journals, and research sponsors involved in paleoclimate research to improve access to data and methods.25

This is not an isolated example of a research field with highly charged policy implications. Research data and findings have a substantial influence on a growing number of issues, ranging from arms control to air quality, endangered species, environmental toxins, and school vouchers.26 In many of these cases, researchers are being asked to contribute information in areas


Mann, Michael E., Raymond S. Bradley, and Malcolm K. Hughes. 1998. “Global-scale temperature patterns and climate forcing over the past six centuries.Nature 392: 779–787.


Geoff Brumfiel. 2006. “Academy affirms hockey-stick graph.” Nature 441:1032. The researchers requesting the data and other information were Stephen McIntyre and Ross McKitrick.


Letter from Representatives Joe Barton and Ed Whitfield to Dr. Raymond S. Bradley, June 23, 2005. Available at http://republicans.energycommerce.house.gov/108/Letters/062305_Bradley.pdf.


Letter from Dr. Alan I. Leshner to Representative Joe Barton, July 13, 205. Available at http://www.aaas.org/spp/cstc/docs/05-7–13climatebarton.pdf.


National Research Council. 2006. Surface Temperature Reconstructions for the Last 2,000 Years. Washington, DC: The National Academies Press.


The wording in this paragraph has been changed to correct some factual errors.


See the list of “Examples of Political Interference in Science” maintained by the Union of Concerned Scientists at http://www.ucsusa.org/scientific_integrity/interference/a-to-z-alphabetical.html.

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