President Donald Trump said earlier this week that he read parts of the federal government’s newest climate assessment report but concluded, “I don’t believe it.”

White House press secretary Sarah Sanders was even blunter.

On Tuesday she declared during a briefing that “you have to look at the fact that this report is based on the most extreme modeled scenario, which contradicts long-established trends. Modeling the climate is an extremely complicated science that is never exact.”

“We think this is the most extreme version, and it’s not based on facts,” Sanders added.

The National Climate Assessment Vol. 2 report, released late in the day on Black Friday, the day after Thanksgiving, was prepared by officials from 13 federal departments and agencies and was more than a year in the making.

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The National Oceanic and Atmospheric Administration (NOAA) led the reporting effort, which is collectively known as the U.S. Global Change Research Program (USGCRP).

The USGCRP report’s most sensational claims include these points:

1.) The current era is “the warmest in the history of modern civilization,” due to a 1.8 degree Fahrenheit increase in the average surface temperature around the world.

2.) Sea levels have risen 7-8 inches worldwide at a “rate of rise that is greater than during any preceding century in at least 2,800 years.”

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3.) The frequency of hurricanes and destructive downpours, especially in the northeast region of the U.S., are “increasing in intensity and frequency across the United States and globally and [this] is expected to continue to increase.”

4.) Heat waves across the U.S. will increase in the coming decades because over the next few decades (2021–2050), “annual average temperatures are expected to rise by about 2.5 degree Fahrenheit.”

5.) Destructive wildfires such as the recent Camp Fire in California, which killed dozens of people, have “increased since the early 1980s and [are] projected to further increase in those regions as the climate changes, with profound changes to regional ecosystems.”

The White House response to the report, however, was mild compared to the evaluations of some climate scientists and others.

These people reject the claim of extreme environmentalists that doomsday is right around the corner because people generate greenhouse gases by burning fossil fuels to power cars, heat homes, and complete scores of other daily chores.

After reviewing the report, Norman Rogers, a policy adviser to The Heartland Institute, a think tank based in Illinois, and a former director of operations for Zero Population Growth, said the critical flaw in such climate analyses is that they’re based on groups of data-based models. These, in turn, are based on subjective assumptions favored by their creators.

“The way the models are used to create predictions or projections of future climate is determined by political, not scientific, considerations. The results of the many models are simply averaged together to create an ensemble of climate models that is used to make the doomsday predictions,” Rogers said.

Rogers’ assessment is especially significant because of his earlier work for Zero Population Growth, a radical environmental group co-founded by Paul R. Ehrlich, a Stanford University professor and author of “The Population Bomb,” among other works.

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Pat Michaels, director of the Cato Institute’s Center for the Study of Science, said the USGCRP report “is systematically flawed and requires a complete revision” because it “uses a flawed ensemble of models that dramatically over-forecast warming of the lower troposphere, with even larger errors in the upper tropical troposphere.”

Michaels also noted that “the model ensemble also could not accommodate the ‘pause’ or ‘slowdown’ in warming between the two large El Niños of 1997-8 and 2015-6.”

That error alone renders the report’s warming projections, key to all of its conclusions, little more than “a collection of systematic errors.”

In addition, Michaels said using the flawed models means the report, produced with federal tax dollars, “does not fulfill the ‘maximizing the quality, objectivity, utility, and integrity of information’” provision of the Federal Data Act.

As a result, Michaels argued that “the USGCRP must hit the reset button now. It should use a methodology that works — i.e. a model that works — rather than a family of failures that tout a future of unwarranted gloom and doom.”

He added that “it would also be wise to rely more heavily on a concentration pathway that recognizes the massive worldwide switch from coal to natural gas for both electrical generation and manufacturing. That’s the right way, and the only way to produce a credible assessment.”

“This latest climate report is just more of the same — except for even greater exaggeration, worse science, and added interference in the political process by unelected, self-serving bureaucrats.”

Similarly, former Rep. Tim Huelskamp (R-Kan.), president of The Heartland Institute, said in a statement in response to the climate report that it’s like other politically motivated climate change reports.

“This latest climate report is just more of the same — except for even greater exaggeration, worse science, and added interference in the political process by unelected, self-serving bureaucrats,” Huelskamp said.

“This report from the climate alarmist Deep State in our government is even more hysterical than some United Nations reports,” he said in his statement.

“The idea that global temperatures could rise as much as 12 degrees in the next 80 years is absurd and not a shred of actual data and observation supports that.”

A different sort of climate change report may lie ahead for federal bureaucrats who write assessments like this new one, since Andrew Wheeler, acting administrator of the Environmental Protection Agency, agrees with critics about the flawed models.

“Going forward, I think we need to look at the modeling that’s used for the next assessment,” Wheeler said Wednesday in Washington, D.C., during a Washington Post Live event.

Mark Tapscott is a senior investigative journalist.