Climate scientists have been warning of the threat to global food supplies for decades. Drought, flooding and sea level rise threaten to dramatically reduce the productivity of the world’s key agricultural regions. However, even these dire warnings may have underestimated the threat according to a new study published in the journal Nature Climate Change.
Whereas previous studies have focused solely on yields, this new study examining farming practices in an area in Brazil called Mato Grosso also looked at the way farmers respond to changes in climate. According to Leah VanWey, professor of sociology at Brown and senior deputy director of the Institute at Brown for the Study of Environment and Society:
“If you look at yields alone, you’re not looking at all of the information because there are economic and social changes going on as well… You’re not taking into account farmers’ reactions to climate shocks.”
For example, when the profitability of a crop fell, farmers simply stopped growing it even though a relatively good yield was still achievable. Farmers also stopped planting their usual two crops in order to maximise the profit from just one; thereby halving the normal yield:
“Had we looked at yield alone, as most studies do, we would have missed the production losses associated with these other variables. [Previous studies] may be underestimating the magnitude of the link between climate and agricultural production.”
Van Wey highlights an urgent need to understand how the economics of agriculture interact with changes in climate to give farmers an incentive to continue producing in the face of future food shortages.