Professor Graeme Hammer, a leading Australian crop scientist at The University of Queensland, developed a complex model which explains how agricultural crop yield will be affected by global warming.
The results of his 10 years work was just published in the latest issue of the world’s leading science journal Nature. The article shows evidence that opposite to common beliefs, the expected decline in crop production is not directly related to the increase in temperatures.
This finding goes against numerous studies conducted in the U.S, which state that high temperatures during hot seasons in the American mid-west result in reducing maize production.
Professor Hammer and his team demonstrated that the actual cause is the increased evaporative demand for water. This is why crops need more water, which is unavailable at such times of the year, ultimately leading to lower production.
According to the scientist, although these two factors are related, it has always been assumed that temperatures and heat stress affect the plants productivity. Thanks to the new model, the team was able to clearly separate the two and define the mechanisms better.
Hammer explains what happens by comparing the plant response with the response of the human body to extreme heat conditions. More intensive sweating leads to faster depletion of water reserves in the body and therefore increases the body’s water demand.
By applying the model, Hammer was able to accurately predict the declines in the maize harvest using historical data from the American mid-west for the past 50 years.
