S. Fred Singer, scientist and climate-change skeptic, dies at 95

As some of his predictions came into focus and others faded from view over the next half-century, Dr. Singer came to occupy a different place in the scientific world. Somewhere along the line, Dr. Singer’s views of science became entwined with a libertarian, anti-communist political viewpoint that made him increasingly outspoken and contrarian.

He found a new purpose as a scourge who sought to denigrate other scientists who warned the public about secondhand smoke, greenhouse gas emissions, acid rain and the dangers of a steadily warming climate.

“It’s all bunk,” he often said.

“Stop worrying, don’t worry,” he told a gathering at Colorado State University in 2011. “Nothing you do will have any effect on the carbon dioxide level in the atmosphere. Even if it did have an effect, it won’t affect the planet.”

In 1990, Dr. Singer founded the Virginia-based Science and Environmental Policy Project “to challenge government environmental policies based on poor science.” The group’s mission statement notes that “omitting critical data violates the scientific method” — precisely what Dr. Singer’s critics accused him of doing.

In 2007, he helped launch the Non-governmental International Panel on Climate Change (NIPCC) — a climate-skeptical counterpart to the United Nations Intergovernmental Panel on Climate Change (IPCC).

From climate change to tobacco to air pollution, Dr. Singer held firm to the belief that government regulations were wrong in principle and too costly in practice. Over time, he focused his attention mostly on climate change, becoming perhaps the most prominent scientist speaking out in opposition to a growing body of evidence that rising global temperatures could have a catastrophic effect on the planet.

“There is no debate among any statured scientists of what is happening,” Harvard University earth scientist James McCarthy said in 1997. “The only debate is the rate at which it’s happening.”

Genial and glib, Dr. Singer spoke in a British accent and was eager to spread his views in speeches, articles and interviews.

“There is nothing remotely like scientific consensus that global warming is occurring, or if it is, that it will have disastrous consequences,” he wrote in 1991 in his regular column in the Washington Times. “A respectable body of opinion in the international scientific community holds that any climate warming is as likely to be beneficial as harmful, acting as a hedge against global cooling.”

He dismissed many studies about the dangers of secondhand tobacco smoke and rising temperatures as “junk science.” In 1995, he denounced the Royal Swedish Academy of Sciences for making a “political statement” by awarding the Nobel Prize in chemistry to three scientists who demonstrated that chlorofluorocarbon emissions were depleting the ozone layer.

He had a long association with the Heartland Institute, a libertarian think tank that published some of his books. including “Nature, Not Human Activity, Rules the Climate” (2008).

Among mainstream scientists, Dr. Singer came to be regarded as a charlatan and a crank. He was no longer published in peer-reviewed journals. At least 97 percent of scientists studying the climate, reports indicated, believed that human actions had played a central role in climate change.

“He’s not doing firsthand research, and he does not have regular communication with the rest of the climate research community,” University of Texas climate science professor Rong Fu said in 2009. “I’m not sure he’s even on the fringe.”