Elevated carbon dioxide levels generated as a result of climate change could significantly increase the temperatures found within the canopies of the world’s woodlands and forests, new research has suggested.
A study by researchers from the UK, Ghana and the USA used thermal imaging technology and other sensors to measure the leaf temperatures found at CO2 levels forecast to occur in 2050.
It found that temperatures within the forest canopies rose by around 1.3°C as a direct consequence of increases in CO2 – from an average of 21.5°C under current conditions to 22.8°C at the predicted 2050 CO2 levels.
However, the difference was even more noticeable in extreme heatwaves – as experienced in the UK in the summer of 2022 – where the difference was more than 2°C and the highest recorded leaf temperature rose to around 40°C.
This, the researchers say, is likely caused by reduced levels of transpiration – the process through which water is loss from plants through evaporation from stomatal pores – as plants alter their physiology to reduce water loss when growing in environment where CO2 is elevated.
They believe that as well as having a direct impact on leaf pore structure, it could impact trees’ ability to transmit water back into the environment, which would have a knock-on effect on the water cycle globally.
The researchers say their findings emphasise the importance of cutting global CO2 emissions particularly at a time when there are widespread calls to plant more trees to benefit the environment.
And while they believe oak trees may be to some extent resilient to the changes predicted to occur, the impact on other species is likely to be more marked.
The study, published in the journal Global Change Biology, was led by researchers at the ҹèÊÓƵ working alongside partners from the University of Birmingham, University of Leeds, Northern Arizona University, and the Forestry Research Institute of Ghana.
Dr Sophie Fauset
Mr William Hagan Brown
