After a judge ordered it to do so, the U.S. Environmental Protection Agency offered no evidence supporting its former administrator's claim that human activity is not the main cause of climate change, according to a federal government employee advocacy group.

In a March 9, 2017, appearance on the CNBC program Squawk Box, then EPA administrator Scott Pruitt was asked whether climate change was caused by the release of carbon dioxide due to human activity. "I would not agree that it's a primary contributor to the global warming that we see," Pruitt replied, citing "tremendous disagreement about" the impact of human activity on the climate.

The Public Employees for Environmental Responsibility, or PEER, found that the statements "stand in contrast to published research and conclusions of the EPA" and therefore submitted a request under the Freedom of Information Act, or FOIA, for the EPA to produce the documents that informed Pruitt's conclusions. PEER specifically requested any evidence in Pruitt's possession related to his position and asked if the EPA had any research supporting the former administrator's position.

When the EPA failed to respond to the request in the time allowed under the statute, PEER sued the agency to compel the release of the documents. Responding to the lawsuit — PEER v. EPA (17-652 (BAH)) — the EPA argued that the request is "an impermissible attempt to compel EPA and its administrator to answer questions and take a position on the climate change debate." U.S. District Court for the District of Columbia Judge Beryl Howell on June 1 disagreed and ordered the EPA to produce any responsive documents.

In an initial response to the FOIA request, PEER said the EPA in August revealed that before Pruitt vacated his office in July the former administrator admitted to an agency lawyer that he had no data to support his Squawk Box comments.

The EPA has now gotten back to PEER on whether it has any research supporting Pruitt's statements. PEER said a document posted on its website Oct. 11 shows that the EPA provided 11 records related to climate change. All of the records were different versions of the same document, which contained EPA's answers to questions posed by members of the U.S. Senate Committee on Environment and Public Works following Pruitt's testimony in front of the panel on Jan. 30.

In response to questions from Senator Jeff Merkley, D-Ore., Pruitt testified that a so-called "red team, blue team" exercise to re-examine the underpinnings of climate science was "still under consideration" at the EPA.

In written follow-up questions, Sen. Tom Carper, D-Del., asked the EPA whether it could confirm a statement from Jim Lakely, the communications director of the Heartland Institute, that the agency had reached out to the institute "to help identify scientists who could constitute a red team" and the Heartland Institute had been "happy to oblige." Carper also asked whether EPA representatives consulted with any others about potential candidates who could participate in the exercise. "If yes, please provide the names," Carper said.

The EPA declined to address the questions directly, responding: "Administrator Pruitt encourages an open, transparent debate on climate science — with a Red Team/Blue Team exercise being an option discussed to learn more about the questions around climate science."

Sen. Ed Markey, D-Mass., noted in written questions that the statutorily required National Climate Assessment's Climate Science Special Report released by the Trump administration in November 2017 concluded that "human activities, especially emissions of greenhouse gases, are the dominant cause of the observed warming since the mid-20th century."

"Do you disagree with the conclusion made in the Climate Science Special Report by our country's top scientists at 13 federal agencies, including your own, that human activities are the dominant cause of global warming, with 'no convincing alternative explanation?'" Markey asked.

The EPA responded that it "recognizes the challenges that communities face in adapting to a changing climate," and noted it works with state, local and tribal governments to improve infrastructure to protect against the consequences of climate change and natural disasters. EPA added that it acknowledges that human activity is impacting the climate "in some manner," but asserted that the ability to measure "with precision the degree and extent of that impact, and what to do about it, are subject to continuing debate and dialogue."

PEER General Counsel Paula Dinerstein said in a statement that the results of the records search confirm that EPA does not possess any evidence to dispute the widely accepted theory among scientists that humans are the main cause of climate change. "EPA knew from day one there was no needle in its research haystack," she said, noting that the only scientific information EPA could find were 2009 public comments submitted by a since-retired EPA employee. "The agency engaged in a prolonged, expensive snipe hunt to delay this inevitable admission."

The EPA did not respond to a request for comment.