Despite one Climate-gate revelation after another, Al Gore has been remarkably silent. Indeed, since the Copenhagen Climate Summit he hasn't said anything. That is until now. He broke his silence on Sunday in the New York Times with his 1,900+ word op-ed piece. Although some of the piece responds to recent scandals involving the "e-mail messages stolen from the University of East Anglia in Britain" and the errors found in the UN’s Intergovernmental Panel on Climate Change (IPCC) report, much of the response is filled with snide remarks about "climate deniers."

Gore concedes "at least two mistakes" in the UN’s IPCC 2007 report – the predictions about Himalayan glaciers melting and the percentage of the Netherlands that is below sea level -- but he avoids addressing the other serious problems. Take three of the claims that have been widely used to promote the need to quickly adopt an international climate treaty:

1. The IPCC warned that, due to global warming, the world had "suffered rapidly rising costs due to extreme weather-related events since the 1970s." They cited one study to support their claim, but when the research was finally published in 2008, it had a different conclusion than reported by the IPCC: “We find insufficient evidence to claim a statistical relationship between global temperature increase and catastrophe losses.”

2. The IPCC warned that up to 40 percent of the Amazon rain forest might be wiped out by global warming, but the sole source for that claim was a non-refereed report authored by two people who the Sunday Times of London referred to as “two green activists,” one of them with the World Wildlife Fund.

3. The IPCC also asserted that, by 2020, global warming could have reduced crop yields in some African countries by 50 percent. It was one of the report's most widely quoted and sensationalist warnings, but, again, there was no published scientific evidence that backed it up. The original source was merely a position paper issued by the environmentalist group, the International Institute for Sustainable Development. The institute had looked at studies from three African governments, but none of those government studies linked global warming and crop disasters. As Britain’s The Telegraph reported: "The nearest any got to providing evidence for his claim was one for the Moroccan government, which said that in serious drought years, cereal yields might be reduced by 50 per cent. The report for the Algerian government, on the other hand, predicted that, on current projections, 'agricultural production will more than double by 2020.'" Even these calculations were not explicitly based upon based on global warming considerations.

In his commentary for The New York Times Gore dismisses the scandal of the Climate-gate e-mails as simply "e-mail messages stolen from the University of East Anglia in Britain showed that scientists besieged by an onslaught of hostile, make-work demands from climate skeptics may not have adequately followed the requirements of the British freedom of information law."

Yet, there is no evidence that the e-mails were "stolen." It is quite possible that they were leaked by a whistleblower. The researchers broke British laws by not sharing their data, but they were protected because statutes of limitations have passed and now apparently much of the raw original data are missing. If it was so difficult to share the raw data with skeptics at different universities, why could the University of East Anglia share its data with the British Met Office?
Unfortunately, however, the unwillingness to share data isn't just seen with the University of East Anglia: NASA, the British Met Office, and other institutions have all refused to release their raw temperature data. Even worse, there are concerns now that the closing of more than three-quarters of the world's weather stations starting in 1990, primarily in relatively cold areas, may have biased temperature measurements upwards.

One would think that man-made global warming believers, including Mr. Gore, would want the raw temperature data made available as soon as possible so as to clear up any confusion. But Gore makes no such request.

His op-ed also rehashes many old claims, such as the "Arctic ice cap is disappearing and the speed with which some of the large glacial flows in Antarctica and Greenland are melting and racing to the sea." Yet, Antarctica's ice pack, which holds 90 of the earth's ice and 80 percent of it fresh water, has remain essentially unchanged over the last few decades. Gore also ignores that while Arctic sea ice was declining until 2007, recent years have shown the opposite pattern, with it rising by 19 percent.

Politicians, such as Gore, apparently don't appreciate the role that transparency plays in science. But scientists trust others' results much more when they are actually able to examine the data themselves. Gore dismisses these concerns as mere trivialities, but if they are so easy to deal with, why not make sure that the data are provided? Memo to the former Vice President: In this day of computer files and the Internet, sharing data is actually pretty simple.

John R. Lott, Jr. is a contributor. He is an economist and author of "More Guns, Less Crime" (University of Chicago Press). The book's third edition will be published in May.

John R. Lott, Jr. is a columnist for He is an economist and was formerly chief economist at the United States Sentencing Commission. Lott is also a leading expert on guns and op-eds on that issue are done in conjunction with the Crime Prevention Research Center. He is the author of nine books including "More Guns, Less Crime." His latest book is "The War on Guns: Arming Yourself Against Gun Control Lies (August 1, 2016). Follow him on Twitter@johnrlottjr.