Copenhagen—Even under this city’s low, leaden skies, at least one thing remained clear as leaders from 193 countries gathered to negotiate climate agreements: one ton of carbon dioxide emitted in the U.S. has the same effect as one ton emitted in India or anywhere else. That simple truism is part of a huge body of data pointing to humanity’s effect on climate, and for most negotiators, the weight of that evidence seems to have crushed any doubt they may have felt in the wake of the 1,000-plus e-mails and computer code stolen from the University of East Anglia’s Climatic Research Unit (CRU).
The theft made headlines as “Climategate” in November, and many private correspondences among scientists became public. Climate contrarians and politicians, including Senator James M. Inhofe of Oklahoma, have claimed that the messages show that climate science was far from settled, that “tricks” were used and that researchers hid unfavorable data.
In fact, nothing in the stolen material undermines the scientific consensus that climate change is happening and that humans are to blame. “Heat-trapping properties can be verified by any undergraduate in any lab,” notes climate scientist Katharine Hayhoe of Texas Tech University. “The detection of climate change, and its attribution to human causes, rests on numerous lines of evidence.” They include melting ice sheets, retreating glaciers, rising sea levels and earlier onset of spring, not to mention higher average global temperatures.
“Further increases in greenhouse gases will lead to increasingly greater disruption,” said meteorologist Michael E. Mann of the Pennsylvania State University in a December 4 conference call with reporters. Mann was among the scientists whose e-mails were exposed.
Some of the kerfuffle rests on a misreading of the e-mails’ wording. For example, “trick” in one message actually describes a decision to use observed temperatures rather than stand-in data inferred from tree rings. Instead of implying deception, the word itself in science often refers to a strategy to solve a problem. Even those scientific papers specifically challenged by the e-mails—one message vowed to keep them out of a report by the United Nations’s Intergovernmental Panel on Climate Change “even if we have to redefine what the peer-review literature is”—nonetheless made it into the most recent IPCC report.
Even if the CRU data “were dismissed as tainted, it would not matter,” argues IPCC contributor Gary Yohe of Wesleyan University. “CRU is but one source of analysis whose conclusions have been validated by other researchers around the world.” Other sources include NASA’s Goddard Institute for Space Studies, the National Oceanic and Atmospheric Administration’s National Climatic Data Center, and even the IPCC, all of which provide access to raw data.
But the messages revealed at least one lapse in judgment when CRU director Phil Jones sent Mann an e-mail asking him to delete any correspondence related to “AR4,” referring to an upcoming IPCC report. “To my knowledge, no one acted on that request. I did not delete any e-mails,” Mann said. The continuing existence of the e-mail itself would seem to support his contention, although his response at the time was to agree to contact a fellow scientist, “Gene,” as requested by Jones, who has stepped down as CRU director.
The stolen e-mails may ultimately provide a sociological window into the climate science community. “This is a record of how science is actually done,” notes Goddard’s Gavin A. Schmidt. Historians will see “that scientists are human and how science progresses despite human failings. They’ll see why science as an enterprise works despite the fact that scientists aren’t perfect.”