Let’s put aside the politically hot topic of the reality of climate change and just assume it is real. Should this be so, what will be the change in our world, say, by 2100? A paper by Solomon Hsiang et al. (School of Public Policy, University of California, Berkeley) uses climate science and economic analyses to forecast climate-induced changes by counties in the U.S.A. (Hsiang, S.; Kopp, R. et. Al. Estimating economic damage from climate change in the United States. Science June 30, 2017, 356[6345],1362–9). Specific topics include agriculture, crime, costal storms, energy, human mortality, and labor productivity. These metrics increase quadratically with global mean temperature increase in increments of 1 °C.
By doing nothing, the poorest third of American counties will suffer a decline in a county gross domestic product (GDP) in the range of 2 to 20% with 90% probability. In the Deep South from Texas eastward, the loss is as high as 28%. In contrast, counties in the U.S.’s northern tier are forecast to show gains in the range of 5 to 13%. This is a huge shift in economic opportunity. For example, my home state of California predicts continued growth in counties along the Pacific coast, but the trend reverses as one moves east to the Central Valley and Sierras.
If the climate change is +8 °C, electricity demand will increase almost 50% for the U.S.A. Much of this is probably due to increases in demand for air conditioning (Friedman, L. Fixing a major piece of the climate puzzle. NY Times July 14, 2017, p. A4). In contrast, agricultural yields are forecast to decline by 40 to 60%. Some of these numbers seem extreme today, but the mathematical models reported in the paper seem to allow for updates and refined predictions based upon more recent data.
The report displays the data with heat maps of American counties. Thus, readers can quickly locate places of interest, including where they live.
This series of forecasts would be interesting to commercial firms such as banks, including mortgage investors. How would you feel if you loaned money secured by a property in Texas or South Florida compared to a similar loan on a property in Minneapolis, MN? Mortgage loans may be for 30 years, but property values can change with economic outlook.
But for most of us, with a 30–60-year planning horizon: Go North!
Robert L. Stevenson, Ph.D., is Editor Emeritus, American Laboratory/Labcompare; e-mail: [email protected].