"THE AGE OF climate panic is here," declared David Wallace-Wells, author of The Uninhabitable Earth: Life After Warming (Tim Duggan Books), in a February 2019 New York Times op-ed. He's certainly right about the panic. University of Cumbria Professor of Sustainability Leadership Jem Bendell predicts that man-made climate change will result in a "collapse in society" in about 10 years. Novelist Jonathan Franzen has warned that it will soon produce "massive crop failures, apocalyptic fires, imploding economies, epic flooding, hundreds of millions of refugees fleeing regions made uninhabitable by extreme heat or permanent drought."
Are they right?
My first article in Reason related to global warming appeared in 1992. It was a report on the Earth Summit in Rio de Janeiro, where the United Nations Framework Convention on Climate Change was negotiated. By signing the treaty, I noted, the "United States is officially buying into the notion that 'global warming' is a serious environmental problem" even as "more and more scientific evidence accumulates showing that the threat of global warming is overblown."
But in subsequent decades, as I continued to cover the science and policy of global warming, I began slowly--too slowly for some--to change my mind. In 2006, I wrote that "I now believe that balance of evidence shows that global warming could well be a significant problem."
I have spent the last several months revisiting the question, trying to figure out if the current level of "climate panic" is scientifically justified. The earth is indeed warming. Climate researchers uncontroversially agree that the average global surface temperature has increased by about 1 degree Celsius since the 19th century. About half of that increase has occurred during the last 30 years. As the planet has warmed, mountain glaciers around the world have been shrinking, Arctic sea ice has been declining, rainstorms have become somewhat fiercer, the area affected by extreme droughts has been expanding, the amount of heat being absorbed by the world's oceans has been increasing, and the global sea level has been rising.
Past those points of scientific consensus, intense disputes begin straightaway. Researchers disagree about how much of the warming can be attributed to increases in the concentration of greenhouse gases in the atmosphere. They clash over which temperature records are more accurate with respect to how fast the earth is warming. They debate whether or not the sea level is rising at an accelerated rate that threatens to inundate many of the world's biggest cities. And they argue about whether the predictions generated by complicated climate computer models can be trusted enough to guide policy.
I have unhappily concluded, based on the balance of the evidence, that climate change is proceeding faster and is worse than I had earlier judged it to be. There are still big scientific uncertainties, such as just how sensitive the global climate is to a given increase in atmospheric greenhouse gas concentrations. And the proper public policy remains far from clear. Still, most of the evidence points toward a significantly warmer world by the end of the century--probably more than 2 degrees Celsius above the preindustrial level. Such a...