Traditional studies may be underestimating the impact of climate change on agriculture, because they don’t take into account “farmers’ reactions to climate shocks,” says a new study in Nature Climate Change.
When temperatures start to rise, social and economic factors play into farmers’ decisions about planting, and can affect crop yield as much as the weather itself. For example, farmers may react by planting fewer acres or crops, because doing so isn’t profitable. Or they may choose not to double-crop (plant another crop during the same season) as they normally would.
Researchers from Brown and Tufts universities found that farmers in the Mato Grosso region of Brazil, (the source of 10 percent of the world’s soybeans in 2013) planted fewer total acres and decreased the amount of double-cropping when temperatures rose by just 1 degree Celsius. Such planting decisions accounted for 70 percent of the overall loss in production, compared to 30 percent from crop yield alone.
The study points to new opportunities for shaping climate-change policies. “We may need to figure out a way to create incentives — credit products or insurance — that can reduce farmers’ responses to climate shocks,” said Leah VanWey, professor of sociology at Brown and senior deputy director of the Institute at Brown for the Study of Environment and Society.
A second climate-change study found that up to 30 percent of sub-Saharan land planted to maize (corn) and bananas, and up to 60 percent of the area’s bean acreage, will be unviable by the end of the century. Local communities will be affected by the loss, but so will many countries that import products from the region. The study said that sub-Saharan Africa will have to significantly transform its agriculture if it is to continue producing food crops. Potential “transformations” include shifting to new crops, improving irrigation systems or, in extreme cases, abandoning farming altogether. Also published in Nature Climate Change, the study offers one of the first timeframes for how implementing policies and new farming practices can minimize farm failure.
The study’s researchers were from CGIAR, a global agricultural research partnership. Co-author Dr. Andy Jarvis, who heads the CGIAR research program on Climate Change, Agriculture and Food Security, said: “It can take decades to adjust national agricultural development and food security policies. Our findings show that time is running out to transform African agriculture.”