Mr. Pruitt, for instance, is replacing dozens of members on the E.P.A.’s scientific advisory boards; in March, he dismissed at least five scientists from the agency’s 18-member Board of Scientific Counselors, to be replaced, according to a spokesman, with advisers “who understand the impact of regulations on the regulated community.” Last month the National Oceanic and Atmospheric Administration dissolved its 15-member climate science advisory committee, a panel set up to help translate the findings of the National Climate Assessment into concrete guidance for businesses, governments and the public.

In June, Mr. Pruitt told a coal industry lobbying group that he was preparing to convene a “red team” of researchers to challenge the notion, broadly accepted among climate scientists, that carbon dioxide and other emissions from fossil fuels are the primary drivers of climate change.

Andrew Dessler, a professor of atmospheric science at Texas A&M University, called the red team plan a “dumb idea” that’s like “a red team-blue team exercise about whether gravity exists.” Rick Perry, the energy secretary, former Texas governor and climate skeptic, endorsed the idea as — get this — a way to “get the politicians out of the room.” Given his and Mr. Pruitt’s ideological and historical financial ties to the fossil fuel industry, it is hard to think of a more cynical use of public money.

Even the official vocabulary of global warming has changed, as if the problem can be made to evaporate by describing it in more benign terms. At the Department of Agriculture, staff members are encouraged to use words like “weather extremes” in lieu of “climate change,” and “build soil organic matter, increase nutrient use efficiency” instead of “reduce greenhouse gases.” The Department of Energy has scrubbed the words “clean energy” and “new energy” from its websites, and has cut links to clean or renewable energy initiatives and programs, according to the Environmental Data & Governance Initiative, which monitors federal websites.

At the E.P.A., a former Trump campaign assistant named John Konkus aims to eliminate the “double C-word,” meaning “climate change,” from the agency’s research grant solicitations, and he views every application for research money through a similar lens. The E.P.A. is even considering editing out climate change-related exhibits in a museum depicting the agency’s history.

The bias against science finds reinforcement in Mr. Trump’s budget and the people he has chosen for important scientific jobs. Mr. Trump’s 2018 federal budget proposal would cut nondefense research and development money across the government.