Environmentalist Peter Gleick, president of the Pacific Institute, has an article at the Huffington Post in which he admits he is the source of the leaked Heartland Institute documents — but Gleick denies making changes to any documents: The Origin of the Heartland Documents.

This explains why the timestamp on the document Heartland claims was “faked” is in the Pacific time zone, and also why that particular document was a scanned image; Gleick says he received the original in the mail, anonymously.

At the beginning of 2012, I received an anonymous document in the mail describing what appeared to be details of the Heartland Institute’s climate program strategy. It contained information about their funders and the Institute’s apparent efforts to muddy public understanding about climate science and policy. I do not know the source of that original document but assumed it was sent to me because of my past exchanges with Heartland and because I was named in it.

Given the potential impact however, I attempted to confirm the accuracy of the information in this document. In an effort to do so, and in a serious lapse of my own and professional judgment and ethics, I solicited and received additional materials directly from the Heartland Institute under someone else’s name. The materials the Heartland Institute sent to me confirmed many of the facts in the original document, including especially their 2012 fundraising strategy and budget. I forwarded, anonymously, the documents I had received to a set of journalists and experts working on climate issues. I can explicitly confirm, as can the Heartland Institute, that the documents they emailed to me are identical to the documents that have been made public. I made no changes or alterations of any kind to any of the Heartland Institute documents or to the original anonymous communication.

I will not comment on the substance or implications of the materials; others have and are doing so. I only note that the scientific understanding of the reality and risks of climate change is strong, compelling, and increasingly disturbing, and a rational public debate is desperately needed. My judgment was blinded by my frustration with the ongoing efforts — often anonymous, well-funded, and coordinated — to attack climate science and scientists and prevent this debate, and by the lack of transparency of the organizations involved. Nevertheless I deeply regret my own actions in this case. I offer my personal apologies to all those affected.

I’m struck by the great difference between this case and “Climategate,” in which nobody has ever come forth and admitted being the thief, and in which the “revelations” were utter nonsense, plucked out of context to create a deliberately misleading impression.

We now know beyond any doubt that the revelations about Heartland’s efforts to subvert climate science and mislead the public, and about their support and funding from energy industries and lobbyists, were completely accurate.