Study: Rising Carbon Dioxide Has Varied Effects on Agricultural Production
Although many people have argued that rising carbon dioxide levels would benefit crop production, a recent model of the effects of increased CO2 shows that it's not that simple and that elevated levels could have a much less positive effect on plant photosynthesis than previously predicted.
Purdue University researchers tested the effects of increased CO2 and warmer temperatures on plant water use. Although increased carbon dioxide and warmer temperatures generally improve photosynthesis, in these experiments the researchers found that pores on plant leaves, known as the stomata, were predicted to narrow in these conditions, reducing the amount of moisture plants release into the air.
Although this change may mean some plants are more efficient in their water use in some arid regions, overall this change in plant physiology will have its own climate effects, resulting in less rainfall in some regions, damaging plants and crop yields, says Qianlai Zhuang, professor of earth and atmospheric science.
"This study reveals that while increasing atmospheric carbon dioxide can directly strengthen plant uptake of CO2, it can also reduce plant transpiration, influence global precipitation patterns, and increase warming locally," he says.
https://phys.org/news/2017-03-co2-due-climate-agriculture.html
Rod Waddington