Our Research Air pollution impacts on global crop yields

Photo credit: Heald research team

Principal Investigator

Colette Heald

Professor
Associate Department Head of Civil and Environmental Engineering
Department of Earth, Atmospheric and Planetary Sciences
Department of Civil & Environmental Engineering

Colette L. Heald is a Professor in the Departments of Civil and Environment Engineering & Earth, Atmospheric, and Planetary Sciences at MIT. She received her undergraduate degree in Engineering Physics from Queen’s University in Canada in 2000, and her PhD in Earth and Planetary Science from Harvard University in 2005.She held the NOAA Climate and Global Change postdoctoral fellowship at the University of California Berkeley from 2006-2007. Colette heads the Global Atmospheric Composition and Chemistry Modeling Group at MIT. She is a Fellow of the American Geophysical Union. Professor Heald is an international leader in biosphere-atmosphere interactions, aerosol sources and transformations, and the connections between atmospheric chemistry and climate. She is rooted at the intersection of modeling and observational analysis, with a strong emphasis on the integration of the two.

Challenge:

What threat does air pollution pose to global food security, and what is the role of particulate matter in its effect?

Research Strategy

Simulated the effects of particulate matter on solar radiation
Translated observed changes to global crop yield estimates
Compared findings with effects of ozone to understand future influence on crop production

Project description

Growing populations are exerting tremendous pressure on the global food supply. Environmental stresses put food security at even greater risk. Ozone air pollution has been shown to extensively damage crops at a cost of billions to the agricultural sector, yet our understanding of the air pollution impacts on food production is incomplete. To date, no study has examined the global impact of particulate atmospheric pollution on crop yields. Particulate matter (PM) is the leading environmental cause of premature mortality, responsible for many of the dramatic air pollution events seen in cities. By scattering and absorbing solar radiation, PM has two effects on plants (1) it reduces total solar radiation reaching the surface, reducing plant productivity, and (2) it increases the fraction of diffuse radiation, which can be more effectively used by the entire plant canopy, thereby increasing plant productivity. There is a critical need to examine these effects on crop yields at a global scale, under realistic local conditions. This project provided the first comprehensive estimate of food production risks associated with air pollution. The research team combined global modeling tools with both statistical and mechanistic descriptions of crop response to estimate the impact of particulate air pollution on both present-day and 2050 crop yields. Particulate pollution may act to reinforce or counteract the damaging effects of ozone pollution, depending on the local environment; the research team contrasted these two effects in this project. This analysis provides vital new insights into the food security risks associated with air pollution and the need for associated local scale crop adaptation.

Outcomes

Simulated air pollution levels for 2010 and 2050 using GEOs-Chem and RRTMG (GC-RT) and used these estimates to predict impact of air pollution on crop yields
Conducted “offline” analysis of the impact of air pollution on crop yield utilizing present knowledge of ozone damage and literature detailing statistical relationship between radiation and crops
Conducted “online” analysis of impact of particulate matter (PM) and nitrogen on crop yield using DSSATmodel
Determined that the impact of PM on crop yield is substantial but can be deterred by factors such as nitrogen and water and is subject to physiological limits of crops