With the increase in greenhouse gas emissions during past decades, continuous global warming resulted into record-breaking global temperature increase. According to the Paris Agreement in 2015, the global community agreed to limit global warming to 2.0oCin relation to the pre-industrial level, with the stated ambition to attempt to cap warming at 1.5oC. Efforts to ensure global warming to below 2°C are under way. Crop production is one of the sectors mostly impacted by climate variability, and the projected changes could cause further vulnerability for achieving global food security.
Now, a new study published in Global Change Biology gave projections about global wheat production - the most significant single crop in terms of human consumption, under 1.5°C and 2.0°C global warming. An international research group, including scientists from 47 scientific institutions in 18 countries, evaluated the impacts of the 2015 Paris Agreement range of global warming (1.5oC and 2.0oC warming above the pre-industrial period) on global wheat production and local yield variability. They used the multi-crop model ensemble and the multi-climate model ensemble, including the WheatGrow model which was developed by National Engineering and Technology Center for Information Agriculture at Nanjing Agricultural University, P. R. China, to make projections about the future wheat yields.
The results show that projected global wheat production will increase by 1.9% under the 1.5oC scenario and 3.3% under the 2.0oC scenario, compared to a baseline of 1980-2010, when considering changes in local temperature, rainfall and global atmospheric CO2 concentration. Most of increase in wheat production can be attributed to the increase in atmospheric CO2 concentration, which will enhance photosynthesis in wheat crop.
“Despite mostly positive impacts on global average grain yields, the frequency of extremely low yields and yield inter-annual variability will increase tremendously under both warming scenarios for some of the hot growing locations, including locations from the second largest global wheat producer - India, which supplies more than 14% of global wheat”, said by Prof. Yan Zhu, the corresponding author of this study, also Dean of College of Agriculture at Nanjing Agricultural University.
Senthold Asseng, a professor from Department of Agricultural and Biological Engineeringat University of Florida in U.S.A and the co-corresponding author of this study, also stressed the fact that “The projected global impact of warming <2oC on wheat production are therefore not evenly distributed and will affect regional food security across the globe as well as food prices and trade”.
About the implications, the researchers wrote “Assessing the potential 1.5°C and 2.0°C warming impacts on global or regional crop production can help to addressing food security and agricultural adaptation more effectively.”
Figure. Projected impacts of the 1.5°C global warming on wheat grain production for major wheat growing countries.