Tree roots in the mountains 'act like thermostat for global climate' | University of Oxford
Tropical rain forests in Peru
Tropical rain forests in Peru



Researchers from Oxford and Sheffield Universities have found that temperatures affect the thickness of the leaf litter and organic soil layers, as well as the rate at which the tree roots grow. In a warmer world, this means that tree roots are more likely to grow into the mineral layer of the soil, breaking down rock into component parts which will eventually combine with carbon dioxide. This process, called weathering, draws carbon dioxide out of the atmosphere and cools the planet. The researchers say this theory suggests that mountainous ecosystems have acted like the Earth’s thermostat, addressing the risk of 'catastrophic' overheating or cooling over millions of years.



Lead researcher Chris Doughty, from the School of Geography and the Environment at the University of Oxford, said: 'This is a simple process driven by tree root growth and the decomposition of organic material. Yet it may contribute to Earth's long-term climate stability. It seems to act like a thermostat, drawing more carbon dioxide out of the atmosphere when it is warm and less when it is cooler.

'A series of climatic events over the last 65 million years have resulted in global temperatures rising and falling. However, the weathering process that regulates carbon dioxide in the atmosphere may be buffered by forests that grow in mountainous parts of the world. In the past, this natural process may have prevented the planet from reaching temperatures that are catastrophic for life.'

Co-author Yadvinder Malhi, Professor of Ecosystem Science at Oxford University, said: ‘This study shows how trees can act as brakes on extreme climate change, and the roots of trees in tropical mountains such as the Andes play a disproportionate role. However, these responses take thousands to millions of years and cannot do much to slow the rate of global warming we are experiencing this century.’