Climate-change science is “settled,” say proponents of anthropogenic (human-induced) global warming, or AGW: the earth is getting warmer, and human activities are the reason. The Intergovernmental Panel on Climate Change (IPCC), set up by the United Nations in 1988, has issued five assessment reports since its founding. In its most recent, in 2013, the IPCC stated that it was now “95 to 100 percent certain” that human activities—especially fossil-fuel emissions—are the primary drivers of planetary warming. Frequent news reports—such as the story of the melting of the West Antarctic Ice Sheet, a process that some scientists say is irreversible—seemingly confirm these conclusions.

And yet, highly credentialed scientists, including Nobel Prize–winning physicist Ivar Giaever, reject what is often called the “climate consensus.” Giaever resigned from the American Physical Society in protest of the group’s statement that evidence of global warming was “incontrovertible” and that governments needed to move immediately to curb greenhouse-gas emissions. Sixteen distinguished scientists signed a 2012 Wall Street Journal article, in which they argued that taking drastic action to “decarbonize” the world’s economy—an effort that would have major effects on economic growth and quality of life, especially in the developing world—was not justified by observable scientific evidence. And, like Giaever, they objected to the notion of a climate consensus—and to the unscientific shutting down of inquiry and the marginalization of dissenters as “heretics.” Most recently, renowned climate scientist Lennart Bengtsson stepped down from his post at a climate-skeptic think tank after he received hundreds of angry e-mails from scientists. He called the pressure “virtually unbearable.”

Another dissenter, the American atmospheric physicist Murry Salby, has produced a serious analysis that undermines key assumptions underpinning the AGW worldview. His work and its reception illustrate just how unsettled climate science remains—and how determined AGW proponents are to enforce consensus on one of the great questions of our age…

Read the full article at City Journal: An Unsettling Climate