The dangers of climate change to world food security are well known, but new research suggests that by 2050 our ability to produce food may be lowered by up to 10 per cent due to rising air pollution.
"Human activities have increased the concentration of carbon dioxide in earth's atmosphere by over 30 per cent during the past 200 years and this figure is expected to double by the end of the century," said Arnold Bloom, lead author of the study published in Nature Climate Change. "Our report found this change in air pollution inhibits the growth of field-grown wheat by 10 per cent."
Bloom said air pollution would affect both urban and rural farming alike. Field-grown wheat is a staple crop for most developing countries, so if not addressed these findings show food security will suffer more than predicted. Adding to the crisis, worldwide food demand is set to rise by 50 per cent by 2050.
"Climate change is already making people hungry," said Robin Willoughby, Oxfam UK's policy adviser on food. "Rising temperatures and increasingly extreme and erratic weather patterns are making it harder to grow enough food to eat.
"Unfortunately, the situation is likely to get worse, placing an additional burden for our humanitarian work as droughts and flooding become more frequent. Climate change threatens to put the fight to eradicate hunger back by decades."
So, what will rising air pollution mean for aid workers delivering food in developing countries? "As air pollution begins to effect food supply, NGOs need to promote farming techniques that conserve water and soil, especially in dry or desert areas," said Paul Cook, advocacy director for Tearfund, an international NGO.
"NGOs also need to work to give farmers in developing countries access to up-to-date information on weather, climate, disaster early warning, and markets, so they can make well-informed plans and responses. Farmers need to experiment with agricultural approaches, so they are equipped to find solutions in an ever-shifting climate."
Cook said the development sector needed to focus on getting wealthy countries to eat less. "NGOs need to help people in rich countries consume less and consume differently, and campaign for government action on climate change," he said. "In this way, we may see a different story for issues like food insecurity in 2050."
However, some in the sector dismissed the findings, and said future food security would depend more on socio-economic factors than climate change.
"The people that analyse the biophysical data on CO2 effects on plants are not those who can speak volumes about food security," said Francesco Tubiello, natural resources officer for the monitoring of greenhouse gas emissions in agriculture for the United Nation's Food and Agriculture Organisation.
"This is because food security and malnutrition have significant dimensions that have nothing to do with science, and much to do with socio-economics.
"The reduction or increase of absolute quantities of food is a very weak proxy for current and future food security levels, as the latter depends more on the economic laws of supply and demand and of redistribution, and on non-biophysical things such as poverty, infrastructure, politics and management."