U.S. agriculture in a modern Dust Bowl drought

Abstract:

Drought-induced agricultural loss is one of the leading weather-related harms to the U.S. economy, but little is known about the effects of extreme droughts or of consecutive multi-year drought events on agriculture. Three droughts in the early 1930s make the Dust Bowl era the driest and hottest for agriculture in modern U.S. history and a useful analog to study extreme weather and its impact on human society. Improvements in technology and farm management over the last eight decades have dramatically increased average crop yields in the U.S., but the elimination of most non-climatic crop stresses means rainfed yields are now more tightly linked to climate. To understand how a 1930s-type drought would affect agriculture in the modern U.S., we drive empirical and biophysical process-based crop models with 1930s weather -- with and without increases in mean temperature -- to estimate effects of successive droughts on current and near-future U.S. maize, soy and wheat production. Our results suggest that Dust-Bowl-type droughts today would have unprecedented consequences for agricultural productivity, with single-year losses up to ~50% larger than the central U.S. drought of 2012, one of the most severe for modern agriculture. Sensitivity tests imply that damages at these extremes are highly sensitive to temperature. If extreme drought conditions are even modestly warmer (1-4 ^oC), single-year losses jump to more than twice the 2012 drought. Assuming that repeated crop failure over a relatively short period is likely to induce changes to land-use and management, we find that a future Dust-Bowl-like drought, especially under higher temperature scenarios, could lead to significant long-term consequences for U.S. agriculture. Changes in climate may increase the severity and frequency of future droughts, so understanding the complex interactions of weather extremes and a changing agricultural system is critical to effective preparation and response if and when the next Dust Bowl strikes.