A new global crop-yield analysis has revealed that global warming has already decreased the rate of growth for major crop harvests over the past 30 years.
Over the past century, the rapidly rising population of the world has been able to be fed because of rising yields of four major food crops: maize (corn), wheat, rice and soybeans. 75 percent of our nourishment comes from these four crops, either directly, or indirectly via the animals we eat.
According to the new analysis of crop yields, human induced climate change is partly responsible for the declining rise of crop yields. It has cut wheat harvests by 5.5 percent and maize by 3.8 percent from what would have been expected since 1980.
The study used U.N. Food and Agriculture Organization data going back to 1980 for crop yields in all the major crop-growing regions. This data was aligned with temperature and precipitation data for crop growing seasons. It was found that increasing temperatures were reducing crop yields. The analysis found that precipitation does not seem to be having an impact so far.
The analysis concluded that the additional CO2 in the atmosphere, from fossil fuel burning and industrial agricultural practices, actually helped rice, soybeans and wheat grow, and increased yields by about 3 percent during the 30 years. For wheat on the other hand, it was found that temperature effects are already overriding the effects of CO2.
The analysis found that the loss of yield has contributed directly to higher food prices, as much as 18.9 percent to the average price of a given crop over the period of the study.
It was found that some crop growing areas have not yet been affected but are likely to be, as further rising global CO2 levels are inevitable. At least another 1 degree Celsius of global temperature rise by the end of this century is already locked-in.