Previous assessments of climate change impact on crop yields commonly combine future climate scenarios and process-based crop models to project future yields for a limited number of crops for 2050 or later. At higher levels of warming, strong yield losses are predicted in lower latitudes especially for maize and wheat crops. Although these results provide insights into long-term future changes, there are large uncertainties in both the modeled climate projections and in the crop model parameters. Hence, the distant time horizon, small number of crops, and coarse resolution limit the results’ utility for stakeholders and policy makers to develop goals and strategies.
Assessing the impacts of recent climate change complements long-term forecasts and identifies which crops and places are already at greater risk. Since the 1970s, global surface temperature warmed at an average of 0.16 to 0.18 degrees-C per decade, a rate higher than any period since the industrial revolution. During that same period, we find that the growing season temperature, over all harvested areas for the top 10 global crops – barley, cassava, maize, rice, oil palm, rapeseed, sorghum, sugarcane, soybean and wheat – increased 0.5 to 1.2 degrees-C. Growing season precipitation changes were more variable; from a decrease of 3.4 mm averaged over all sugarcane harvested croplands to an increase of ~19 mm averaged over all oil palm harvested croplands…
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