A CBS Evening News report on emails reportedly stolen from the University of East Anglia Climate Research Unit (CRU) claimed that an email reference to a "trick" to "hide the decline" showed that scientists had "manipulate[d] some research" in order to get "the answer they wanted." Numerous scientists have stated that the "trick" of hiding the decline is a legitimate method to compensate for unreliable tree-ring data after 1960 and that the email in question has been distorted; moreover, several climate scientists have emphasized that the distortions of illegally obtained emails in no way undermines the overwhelming consensus on global warming.
CBS News cites "trick" email to claim scientists "manipulate[d]" data to get "the answer they wanted"
CBS: Scientists "talk of using a 'trick' to 'hide the decline' in global temperatures," "which gave them the answer they wanted." Introducing a report on the December 5 broadcast of the CBS Evening News, anchor Jeff Glor asked, "[D]id some scientists fudge the numbers to make climate change look worse than it is?" During the ensuing report, CBS News correspondent Kimberly Dozier claimed that the reportedly stolen CRU emails "have cast doubts on the very science" that a climate change summit in Copenhagen "is based on," and asserted that the emails "seem to show that some of the world's top experts decided to exclude or manipulate some research that didn't help prove global warming exists." As evidence, Dozier claimed:
DOZIER: An email from 1999 shows scientists worked hard to demonstrate an upward trend. They talk of using a "trick" to "hide the decline" in global temperatures. It worked like this: When temperature readings gathered from studying tree rings showed what looked like a decline in temperatures from the 1980s to the present, the scientists added in measurements taken later by more modern instruments, which gave them the answer they wanted.
CBSNews.com: "Climate Change a Hoax?" A version of the report on the CBS News website appeared with the headlined, "Climate Change a Hoax?" Text accompanying the video also states that Dozier is reporting on "whether scientists fudged numbers to over-exaggerate climate change."
Trick" to "hide the decline" was not about getting "the answer they wanted"; it compensated for unreliable tree-ring data
Conservative claims that numbers were "fudge[d]" rely mainly on out-of-context passage from one email. The "decline" in the email Dozier cited referred to a decline in global temperatures based on unreliable tree-ring data, but instrumental temperature data do not show a decline in global temperatures. As Media Matters noted, in a November 26 article, The Morning Call of Allentown, Pennsylvania, reported that Penn State scientist Michael Mann "said his trick, or 'trick of the trade,' for the Nature chart was to combine data from tree-ring measurements, which record world temperatures from 1,000 years ago until 1960, with actual temperature readings for 1961 through 1998" because "scientists have discovered that, for temperatures since 1960, tree rings have not been a reliable indicator." CRU scientist Phil Jones, who wrote the email in question, has also stated that it is "well known" that tree ring data "does not show a realistic trend of temperature after 1960," and the CRU has said that "[t]he 'decline' in this set of tree-ring data should not be taken to mean that there is any problem with the instrumental temperature data." In a November 20 post, RealClimate.org's staff, which is comprised of several working climate scientists, including Mann, similarly stated:
As for the 'decline', it is well known that Keith Briffa's maximum latewood tree ring density proxy diverges from the temperature records after 1960 (this is more commonly known as the "divergence problem"-see e.g. the recent discussion in this paper) and has been discussed in the literature since Briffa et al in Nature in 1998 (Nature, 391, 678-682). Those authors have always recommend not using the post 1960 part of their reconstruction, and so while 'hiding' is probably a poor choice of words (since it is 'hidden' in plain sight), not using the data in the plot is completely appropriate, as is further research to understand why this happens.
Several scientists have stated that the word "trick" is being misinterpreted. The (U.K.) Guardian reported in a November 20 article that Bob Ward, director of policy and communications at the Grantham Research Institute on Climate Change and the Environment at the London School of Economics, said of Jones' email: "It does look incriminating on the surface, but there are lots of single sentences that taken out of context can appear incriminating. ... You can't tell what they are talking about. Scientists say 'trick' not just to mean deception. They mean it as a clever way of doing something -- a short cut can be a trick." RealClimate also explained that "the 'trick' is just to plot the instrumental records along with reconstruction so that the context of the recent warming is clear. Scientists often use the term 'trick' to refer to ... 'a good way to deal with a problem', rather than something that is 'secret', and so there is nothing problematic in this at all."
East Anglia professor Watson: "The tree-ring measure declines, but the actual temperatures after 1960 go up." In a December 8 London Times column, Andrew Watson, research professor at the University of East Anglia explained how "hackers have picked choice phrases out of context":
In the one most quoted, the director of the Climate Research Unit (CRU), Phil Jones, talks about using a "trick" to "hide the decline". At first reading, this easily translates as "deceiving [politicians, other scientists, everyone] into believing the world is warming when it is actually cooling".
But it doesn't mean that at all. Jones is talking about a line on a graph for the cover of a World Meteorological Organisation report, published in 2000, which shows the results of different attempts to reconstruct temperature over the past 1,000 years. The line represents one particular attempt, using tree-ring data for temperature. The method agrees with actual measurements before about 1960, but diverges from them after that - for reasons only partly understood, discussed in the literature.
The tree-ring measure declines, but the actual temperatures after 1960 go up. They draw the line to follow the tree-ring reconstruction up to 1960 and the measured temperature after that. The notes explain that the data are "reconstructions, along with historical and long instrumental records". Not very clear perhaps, but not much of a "trick". [London Times, 12/8/09]
Scientists say emails do not undermine consensus on climate change
Distortions of illegally obtained documents from one group of scientists do not undermine overwhelming consensus. Numerous climate researchers have refuted the claim that the hacked emails in any way undermine the global consensus regarding climate change. For example, Rajendra Pachauri, chairman of the United Nations' Intergovernmental Panel on Climate Change, stated that "no individual or small group of scientists is in a position to exclude a peer-reviewed paper from an I.P.C.C. assessment," and that individuals and small groups have no ability to emphasize a result that is not consistent with a range of studies, investigations, and approaches." Gavin Schmidt, a climate scientist at NASA's Goddard Institute for Space Studies, reportedly said: "There's nothing in the e-mails that shows that global warming is a hoax. ... There's no funding by nefarious groups. There's no politics in any of these things; nobody from the [United Nations] telling people what to do. There's nothing hidden, no manipulation. It's just scientists talking about science, and they're talking relatively openly as people in private e-mails generally are freer with their thoughts than they would be in a public forum. The few quotes that are being pulled out [are out] of context. People are using language used in science and interpreting it in a completely different way." Peter Frumhoff, the director of science and policy at the Union of Concerned Scientists and an IPCC author further stated: "We should keep in mind that our understanding of climate science is based not on private correspondence, but on the rigorous accumulation, testing and synthesis of knowledge often represented in the dry and factual prose of peer-reviewed literature. The scientific community is united in calling on U.S. policymakers to recognize that emissions of heat-trapping gases must be dramatically reduced if we are to avoid the worst consequences of human-induced climate change." Anthony Leiserowitz, the director of the Yale Project on Climate Change reportedly told Reuters that "there's no smoking gun in the e-mails from what I've seen."
Dozier advances tired and debunked claim that global warming stopped
Dozier suggests global warming has stopped or reversed. During her report, Dozier also said that "1998 was the hottest year since recordkeeping began. But the temperature went down the next year, and it's only spiked a couple of times since."
Scientists reject claim that recent average global temperatures show warming has stopped
Short-term variation does not undermine consensus on warming. Climate experts reject the idea, advanced by Dozier, that the relatively cooler global average temperatures in several of the last 10 years are any indication that global warming is slowing or does not exist. Scientists have identified a long-term warming trend spanning several decades that is independent from the normal climate variability -- which includes relatively short-term changes in climate due to events like El Niño and La Niña -- to which they attribute cooler temperatures in some recent years.
2009 likely to be among five warmest years on record. NOAA's National Climatic Data Center stated in its October Global Analysis that "[f]or the year to date, the global combined land and ocean surface temperature of 14.7 °C (58.4 °F) tied with 2007 as the fifth-warmest January-through-October period on record." Similarly, NASA's Goddard Institute for Space Studies found that the 2009 year-to-date global temperature ranks fifth-warmest out of 130 years. The BBC also reported on November 24 that "[t]his year will be one of the top five warmest years globally since records began 150 years ago, according to figures compiled by the Met Office." The BBC further reported that "[o]ther sources say it could even be the third warmest."
AP: "Statisticians reject global cooling." In an October 26 article headlined, "AP IMPACT: Statisticians reject global cooling," the Associated Press reported: "In a blind test, the AP gave temperature data to four independent statisticians and asked them to look for trends, without telling them what the numbers represented. The experts found no true temperature declines over time." The article later added:
The AP sent expert statisticians NOAA's year-to-year ground temperature changes over 130 years and the 30 years of satellite-measured temperatures preferred by skeptics and gathered by scientists at the University of Alabama in Huntsville.
Statisticians who analyzed the data found a distinct decades-long upward trend in the numbers, but could not find a significant drop in the past 10 years in either data set. The ups and downs during the last decade repeat random variability in data as far back as 1880.
Saying there's a downward trend since 1998 is not scientifically legitimate, said David Peterson, a retired Duke University statistics professor and one of those analyzing the numbers.
Identifying a downward trend is a case of "people coming at the data with preconceived notions," said Peterson, author of the book "Why Did They Do That? An Introduction to Forensic Decision Analysis." [AP, 10/26/09]