By Rob Mitchum
Some of the most important crops risk substantial damage from rising temperatures. To better assess how climate change caused by human greenhouse gas emissions will likely impact wheat, maize and soybean, an international team of scientists has run an unprecedentedly comprehensive set of computer simulations of US crop yields.
The simulations reproduced the observed strong reduction in past crop yields induced by high temperatures, thereby confirming that they capture one main mechanism for future projections. Importantly, the scientists find that increased irrigation can help to reduce the negative effects of global warming on crops – but this is possible only in regions where sufficient water is available. Eventually, limiting global warming is necessary to keep crop losses in check.
“We know from observations that high temperatures can harm crops, but now we have a much better understanding of the processes,” says Bernhard Schauberger from the Potsdam Institute for Climate Impact Research, lead author of the study. “The computer simulations that we do are based on robust knowledge from physics, chemistry, biology; on a lot of data and elaborate algorithms. But they of course cannot represent the entire complexity of the crop system, hence we call them models. In our study, they have passed a critical test…”
…Irrigation could be a means for adaptation – yet only in regions where there’s sufficient water
“The losses were substantially reduced when we increased irrigation of fields in the simulation, so water stress resulting from temperature increase seems to be a bigger factor than the heat itself,” said co-author Joshua Elliott, Computation Institute fellow and researcher at the Center for Robust Decision-Making on Climate and Energy Policy (RDCEP).
When water supply from the soil to the plant decreases, the small openings in the leaves gradually close to prevent water loss. They thereby preclude the diffusion of CO2 into the cells, which is an essential building material for the plants. Additionally, crops respond to water stress by increasing root growth at the expense of above-ground biomass and, eventually, yields…
Continue reading at the Computation Institute…