Two from the National Academies

Past controversies over historical temperature trends and access to research data have resurfaced amid a stir over old e-mail exchanges among climate scientists that were stolen from a university in the U.K. Two National Research Council reports in particular address these issues. Guiding principles for maintaining the integrity and accessibility of research data were recommended in a report released earlier this year, and a 2006 report examined how much confidence could be placed in historical surface temperature reconstructions.

Ensuring the Integrity, Accessibility, and Stewardship of Research Data in the Digital Agerecommends that researchers -- both publicly and privately funded -- make the data and methods underlying their reported results public in a timely manner, except in unusual cases where there is a compelling reason not to do so. In such cases, researchers should explain why data are being withheld. But the default position should be to share data -- a practice that allows conclusions to be verified, contributes to further scientific advances, and permits the development of beneficial goods and services.

Surface Temperature Reconstructions for the Past 2,000 Years examined what tree rings, boreholes, retreating glaciers, and other "proxies" can tell us about the planet's temperature record, and in particular how much confidence could be placed in a graph that became known as the "hockey stick," which depicted a steep rise in temperatures after a 1,000-year period in the last few decades of the 20th century. The committee that wrote the report found sufficient evidence to say with a high level of confidence that the last decades of the 20th century were warmer than any comparable period in the last 400 years. It said less confidence could be placed in reconstructions of temperatures prior to 1600, although proxy data does indicate that many locations are warmer now than they were between A.D. 900 and 1600. Proxy data for periods prior to A.D. 900 are sparse, the report notes.