Posted by: Pamela Mason1 JUL 2014
Food production, climate and climate change are inextricably linked and knowledge that the food system is significantly contributing to climate change is well established. Globally, agriculture is estimated to be responsible for up to 30 per cent of greenhouse gas (GHG) emissions, including methane (CH4) emissions from livestock and rice cultivation, nitrous oxide (N20) emissions from fertilized soils, energy use, fertilizer production and also agriculturally induced land use change. For example, change of land use to grow feed for livestock can disrupt the carbon sink and result in carbon emissions.
Climate, of course has long impacted on agriculture but unless we are able to limit the expected global temperature rise by the end of this century, the quantity and quality of food produced globally will be compromised. However, some perhaps less expected impacts of climate change on nutritional quality of food have recently come to light in the shape of findings from a US meta-analysis published in a research letter in Nature in May this year. This analysis gathered data from seven experimental locations in the US, Australia and Japan and involved 143 comparisons of nutrient concentrations between edible portions of crops grown in normal and elevated atmospheric CO2 levels. The higher concentrations of CO2 were of the order of magnitude expected in the second half of this century and the crops considered included plant foods such as wheat, rice, peas and soybeans.
The analysis indicated that the expected higher levels of CO2 would likely reduce the levels of zinc, iron, and protein in these food crops. Some two billion people live in countries where citizens receive more than 60 per cent of their zinc or iron from these types of crops so this scenario could increase the risk of undernutrition in these vulnerable populations. The authors of the study say that it may be important to develop breeding programmes designed to decrease the vulnerability of food crops to atmospheric CO2. although the potential for technology must not allow us to lose sight of the importance of limiting global increases in CO2.