Land degradation and climate change: Global impact on wheat yields

This study aims at estimating the wheat yield response to future challenges (land degradation and climate change) through a statistical emulator. Data from Global Agro-ecological Zones on the overall wheat yields of 254 provinces for nine main wheat-producing countries and corresponding climate and land suitability information were collected to estimate the statistical relationship between regressors and wheat yields. Once the statistical emulator was calibrated, three scenarios were developed to predict, separately and jointly, the impact of climate change and land degradation on wheat yields and productions in 2050 using the global climate model ECHAM4 information under the B2 scenario with the CO2 fertilization effect. Results showed that under temperature and precipitation projections wheat yield would increase on average by 8% (first scenario); however, the impact of future land suitability (second scenario) on wheat yields would be negative, lowering the average yield (−5%), and overall wheat production (−14%). Combining both effects in the third scenario, future wheat yields would increase by 4.6%, while overall production will decrease by 5.5% since the harvest area will be reduced by 9.7%. Thus, land degradation more than climate change is likely to pose significant challenges for overall wheat production in the future.