Predicted CO2 levels cause marked increase in forest temperatures

Predicted CO2 levels cause marked increase in forest temperatures - University of Plymouth

Researchers used cutting-edge thermal imagining technologies to examine how trees responded to changing environmental conditions

Dr Sophie Fauset and PhD researcher William Hagan Brown are working at a number of sites to explore the potential effects of rising CO2 levels on the world's forests. — Dr Sophie Fauset and William Hagan Brown on a research trip to Ghana (image: University of Plymouth)

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.