Are Cereals Globally in Trouble?
12:00 - 13:00
In the present study we decompose the change in global calorific supply due to climate change by cereal, climate variable, and region, over varying scenarios of economic development and greenhouse gas emissions . We employ a statistical model to estimate the long-run sensitivity of rain-fed and irrigated cereals to the observed variance in daily temperature and precipitation, while attempting to account for the role of historical adaptation. High resolution weather and crop data allows differentiating the response to weather extremes by region (temperate and tropical regions) and management regime. We evaluate the vulnerability of global and regional calorific supply to the risk posed by future exposure to high temperature, low and high precipitation, using results from five different models participating in the Climate Model Inter-comparison Project CMIP5.
Temperature and precipitation shocks have long-lasting effects on yields. Temperate rice and wheat show a much greater ability to recover compared to the same grains cultivated in tropical and subtropical areas. In the latter regions, sorghum and maize fare much better in terms capability to adjust to weather shocks. If we consider the gap between the immediate effect of weather shocks and the lagged response as an indicator of adaptation capacity, results point at low adaptation potentials of especially temperate maize and tropical wheat. Our differentiated results for irrigated and rain-fed cereals suggest that irrigation can be effective to deal with high temperature but not to address heavy rainfall events. Globally, cereals vulnerability is dominated by climate model uncertainty. Regionally, cereals could be in trouble, as the calories supplied by the top producers will decline due to climate change. Estimated elasticity to per capita GDP suggests that crop yields will increase in spite of climate in most places, but poor countries could be in trouble. In a few places economic growth-led crop productivity growth will not be able to offset climate change impacts. In those places, international trade and crop diversification could be important adaptation strategies. The broad-scale assessment of the most and the least impacted cereals across countries can provide inputs for an integrated analysis of mitigation and adaptation and contribute to the debate on prioritizing adaptation investments in agriculture.