AsianScientist (Aug. 15, 2014) – Scientists predict that climate change and uncontrolled air pollution together may severely damage global crop production and increase undernourishment rates, posing a serious threat to global food security and public health. However, the research published in Nature Climate Change also suggests that the damage could be offset by adopting aggressive air pollution regulation and growing more heat-tolerant varieties of crops.
According to the Food and Agriculture Organization of the United Nations, global demand for food is expected to increase by at least 50 percent from now to 2050. Food production to meet the growing demand is severely limited by both climate change and air pollution. High temperature extremes and air pollutants such as ground-level ozone are highly damaging to crops.
“Such global-scale impacts on food production will not only worsen malnutrition problems in developing countries, but also lead to greater fluctuations in food prices that will affect all developed regions including Hong Kong, where most food items are imported,” said Professor Amos P.K. Tai from the Chinese University of Hong Kong.
Growing more heat-tolerant varieties of crops in regions harder hit by warming, known as climate change adaptation, has been identified as an important measure to tackle food insecurity, but how effective will it be, especially when climate change is not the only factor in play? What if some crops are more sensitive to air pollution but not warming? If so, what measures should be taken to ensure food security?
In his study, Prof. Tai used a computer model that simulates future climate and air quality based on a range of future scenarios for human activities, fully considering the intricate interactions between physical and chemical components of the Earth system. It projected that the global average growing season temperature will rise by 1-2°C from now to 2050 in all scenarios considered.
Based on a comprehensive suite of historical relationships between ozone, temperature, crop yield and malnutrition observed worldwide, the study projected that the rise in temperature will reduce global food production by more than ten percent and increase undernourishment rates by more than 30 percent in all scenarios considered.
Prof. Tai then further investigated the impacts of ozone air pollution and found that uncontrolled pollution may further exacerbate the climate impacts, but aggressive ozone regulation worldwide (e.g., by controlling the emissions of hydrocarbons and nitrogen oxides from fossil fuel combustion) can cut down the increase in undernourishment roughly by 50 percent, partially offsetting the climate impacts.
“Depending on the region, some crops are primarily sensitive to either ozone pollution (e.g., wheat) or excess heat (e.g., maize) alone, and this gives us a measure of the relative benefits of climate adaptation of crop cultivars versus ozone regulation for food security in different regions. For regions more seriously afflicted by air pollution such as China, the sensitivity to ozone dominates for almost all crops, and thus pollution control, may be more effective in protecting agriculture than a climate-oriented approach.”
“Such findings are invaluable for guiding agricultural and air pollution policy making, and call for greater collaboration between farmers, agricultural policy planners and air quality managers to achieve coordinated economic and public health goals.”
The article can be found at: Tai et al. (2014) Threat to Future Global Food Security from Climate Change and Ozone Air Pollution.
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Source: Chinese University of Hong Kong.
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