Global Warming Will Be Good

Global Warming Will Be Good

The conventional wisdom about global warming has been that it will be universally devastating for the worlds peoples. This belief is based on an assessment conducted by the Environmental Protection Agency in 1989. The EPA concluded that a 3 to 6 degree C warming would lead to a reduction in global GDP of 1 to 2 percent. Some of the consequences that were imagined included ecosystem collapse, reductions in agriculture yield of between 30 and 40 percent, the spread of vector-borne disease increased water pollution, soaring heat-related deaths, and so on. This bleak outlook has been very influential in the policy debate.

Over subsequent years, however, there has been a sea change in the way experts view the consequences of global warming. Recently, a major study published by Cambridge University Press titled The Impact of Climate Change on the United States Economy concluded that on net global warming will be beneficial. Now one of the authors of that study, Robert Mendelsohn of Yale Universitys School of Forestry and Environmental Studies, has written a monograph for the American Enterprise Institute that summarizes the current state of opinion regarding the impacts of global warming.

One of the biggest changes is that scientists have revised downward the expected warming from 3 to 6 degrees C to 1 to 3.5 degrees C. They have also lengthened the time frame from 50 years to 100 years, giving us much more time to adapt. Previous studies failed to recognize that people adapt to changes in the climate, biasing the results to greater harm than warranted. Heat related deaths, for example, were estimated to rise by between 6,000 and 9,800 deaths per years. But people are not going to sit around and do nothing while the deaths mount. This is borne out by the fact that heat-stress deaths “are higher in cold parts of the United States with high seasonal temperature variability not in stable warm climates.” Moreover, people live longer in warmer climates.

The EPAs assessment claimed that agriculture would suffer large damages from global warming. But new studies that allow for adaptation and carbon fertilization find that agriculture yields will increase. The same can be said for forestry production. Overall, global warming will lead to a slight net benefit for the global economy.

In the policy discussion Mendelsohn concludes, “more expensive abatement programs do not guarantee benefits, and spending trillions of dollars on abatement over the next few decades is simply wasting resources, given what we now understand about climate change.”