A new study published in the Nature Climate Change journal showed the significant interaction between global warming and air pollution in threatening global food supply.
In the past, other studies have shown that the climate change occurring in the whole world has the potential to drastically reduce global food supply. However, these past studies have mostly set aside the interactions between the increasing temperatures brought about by climate change and air pollution, specifically ozone pollution, which has the ability to severely damage planted crops.
The study's findings suggest that lawmakers should take into account both global warming and air pollution as factors to address in solving the issues of food supply security.
The research was led by MIT civil and environmental engineering associate professor Colette Heald, with former CEE postdoc and now Chinese University of Hong Kong's Amos Tai and Colorado State University's Maria Val Martin as part of the team.
The research analyzed the global production of four important food crops, namely rice, corn, wheat and soy, all in all accounting for over half of all the calories that people consume all over the world. The study outlines the difference in the effects of various factors on these crops, depending on the region where they are located. For example, wheat has a high sensitivity to ozone pollution, while corn has a high sensitivity to the heat brought about by global warming.
If all the factors are held equal, global warming may decrease the yields of crops by around 10 percent by the year 2050. Ozone pollution's effects, on the other hand, are more difficult to predict, due to the difference of sensitivities to it by the different crops. In addition, ozone pollution is complicated to identify, as its symptoms such as flecks and discoloration on leaves can be misdiagnosed as plant illnesses.
Global warming and ozone pollution, in addition to independently being able to damage crops, also interact in such a way that leads to even more damage. The increased temperatures brought about by global warming increase ozone production, with the study showing that 46 percent of the damage dealt to crops of soybeans that was thought to have been caused by heat was actually due to higher ozone levels.
The major underlying problem presented by the study is that, while crop yields are expected to be reduced, worldwide demand is expected to increase by 50 percent over the same amount of time to 2050, due to the growing global population and shifting diet trends.
"The increased use of clean energy sources that do not emit either greenhouse gases or conventional air pollutants, such as wind and solar energy, would be doubly beneficial to global food security, as they do not contribute to either climate change or increased surface-ozone concentrations," said Princeton University international affairs and environmental engineering professor Denise Mauzerall.
