The Impact of Water and Heat Stress from Global Warming on Agricultural Productivity and Food Security

This technical report provides new and important results of the impacts of heat stress and water stress on global food production. It dramatically highlights that the costs of inaction greatly exceed the costs of action to resolve the world water crisis.

Global warming is a serious threat to agricultural production and food security. In this report, we present a unique large-dimensional computational global climate and trade model to simulate the impacts of irrigated water and heat stress on agricultural output, total food supply and food security to 2050, termed GTAP-DynW. The model uses GTAP data for 141 countries and regions, with varying water and heat stress baselines, and 65 commodity sectors, both aggregated into 30 countries/regions and 30 commodity sectors. The large dimension captures the heterogeneity of damages across the globe.

Along with a host of other data, the model also employs 18 AEZ land use categories and water use decompositions, with measures from WRI for irrigated water stress and heat stress indicators (as damage functions) from our previous work. The climate change scenarios examined are RCP4.5, RCP8.5-SPP2 and RCP8.5-SSP3. Model results indicate substantial falls (using a calorie metric) in the overall global food supply of 5.8%, 9.7% and 14.2% to 2050, with a resulting nutritional shortage or “food insecurity” for 556 million, 935 million and 1.36 billion additional people, compared to a 2020 baseline, for RCP4.5, RCP8.5-SSP2 and RCP8.5-SSP3, respectively.

Results are also indicated for individual commodities with paddy, wheat, cereal, livestock, meat (animal products) and dairy the most impacted, or with the largest losses in agricultural output.