Research finds water loss from plants a factor in heatwaves
by Tim Howard
WATER loss from vegetation could play a key role in the intensity of heatwaves around the world Australian researchers have found.
The research, published in Nature Scientific Reports, investigated why the projected temperature increases are more than half the change forecast by the IPCC under the business-as-usual model.
“We often underestimate the role of vegetation in extreme temperature events as it has not been included in enough detail in climate models up until this point,” said lead author Dr Jatin Kala from Murdoch University.
“These more detailed results are confronting but they help explain why many climate models have consistently underestimated the increase in the intensity of heatwaves and the rise in maximum temperatures when compared to observations.”
The research predicts heatwaves from Europe to China are likely to be more intense and result in maximum temperatures that are 3°C to 5°C warmer than previously estimated by the middle of the century – all because of the way plants on the ground respond to carbon dioxide in the atmosphere.
The biggest temperature changes were projected to occur over needleleaf forests, tundra and agricultural land used to grow crops.
To get their results the researchers looked at data from 314 plant species across 56 field sites. In particular, they investigated stomata, small pores on plant leaves that take in carbon dioxide and lose water to the atmosphere.
Previously, most climate models assumed all plants trade water for carbon in the exactly same way, ignoring experimental evidence showing considerable variation among plant types. By not accounting for these differences, models have likely over-estimated the amount of water lost to the atmosphere in some regions.
If plants release less water there is more warming and a consequent increase in heat wave intensity.
The study is unique because, for the first time, it used the best available observations to characterise different plants water-use strategies within a global climate model.
Read the full article: Daily Examiner