Climate change affects food supply

(lots of research) - Many studies have demonstrated the ability of global climate change to cut down on food supplies. However, most of these studies ignore the interactions between temperature rise and air pollution - especially ozone pollution , which is known to damage crops.

A new study that includes researchers from MIT (Massachusetts Institute of Technology) has demonstrated that these interactions may be quite important, showing that policy makers need to take both. Factors: global warming and air pollution to calculate when trying to solve food security issues.

This study examined in detail the global production of the top four food crops: rice, wheat, corn and soybeans - accounting for more than half of the global consumption of calories. The study predicts that the effects will vary significantly between different regions, and that some food crops are more impacted than other food crops or more affected by other factors: For example, wheat is very sensitive to ozone exposure, while corn is more adversely affected by temperature.

The study was conducted by Colette Heald, a professor of civil and environmental engineering (CEE) at MIT, CEE's former Dr. Amos Tai and Maria van Martin at Colorado State University. Their research has been described in Nature Climate Change.

Heald explained that, while we all know both higher temperatures and ozone pollution can threaten crops and reduce crop yields , 'no one has considered both of these factors together. at ' . And while rising temperatures are widely discussed, the impact of air quality on crops is less recognized.

The study predicts that impacts may vary by region. In the US, stricter air quality regulations are expected to lead to a sharp reduction in ozone pollution, mitigating the impact of ozone pollution on the crop. But in other regions, the consequences 'will depend on internal air pollution policies , ' Heald said. 'Air cleaning can improve crop yields'.

Research has found that, overall, along with other similar factors, global warming may reduce global crop yields by about 10% by 2050 . However, the effects of ozone pollution are more complex - some food crops are more affected by ozone pollution than other food crops - this shows assessments of pollution control. plays an important role in determining consequences.

Oea pollution can also be difficult to identify, Heald said, because the damage caused by it can easily be confused with other plant diseases, causing leaf spots and leaf blight.

Reducing the yield potential of the crop is very worrying. Global food demand is expected to double by 2050, the authors said, due to population growth and a changing trend in diet in the developing world. So any decline in production is in conflict with the general need of people to increase productivity through crop selection, improved farming methods as well as agricultural land expansion.

While the temperature and ozone, each factor threatening plants independently, these two factors interact with each other. For example, higher temperatures cause increased production of ozone due to the reactions of volatile organic compounds and nitrogen oxides under sunlight. Because of these interactions, the team found that 46% of the damage to soybean productivity that occurred earlier was due to the contribution of temperature, which is actually due to increased ozone.

According to some scenarios, the researchers found that pollution control measures could create a major dent in the predicted decline in productivity due to climate change. For example, while global food production is projected to drop by 15% in a scenario, in an alternative scenario, this ratio is 9% when lowering emissions to lower levels.

Air pollution is even more important when expressing malnutrition in the developing world, researchers found: According to the worse air quality scenario, the rate of malnutrition can an increase of 18-27% in 2050; while under a more optimistic scenario, the rate of malnutrition will still increase, but the level of increase is only half that of the previous scenario.

Agricultural production is 'very sensitive to ozone pollution , ' Heald adds, the findings suggesting the importance of thinking about agricultural impacts of standards and quality standards. air. We understand that ozone is a cause of reduced food production, and the next step needs to be taken to improve air quality.

Denise L. Mauzerall, professor of environmental engineering and international affairs at Princeton University, who did not participate in the study, said: "An important finding, is that the control of pollution levels Gas can help improve food production and improve negative impacts that help offset some of the losses in production caused by climate change , thereby increasing the use of non-generating clean energy sources. emitting or emitting less greenhouse gases, common air pollutants, such as using wind and solar energy, will double the benefits of global food security, when they are not contribute to increasing climate change or increasing surface ozone concentration ".

The study is funded by the National Science Foundation, National Park, and Croucher Foundation.