Scientists warn deforestation is likely to warm the climate a lot more than formerly thought.
An international group of scientists, led by the University of Leeds, explored the way that gases released by trees and vegetation impact the climate.
Their research discovered these reactive gases cool the climate, meaning deforestation would result in higher temperatures than formerly anticipated as less of the gases would be produced. Their findings have been published recently in Nature Communications.
Study lead author Dr Catherine Scott, from the School of Earth and Environment said: “Most previous assessments on the climate impacts of deforestation have focused on the amount of carbon dioxide that would be emitted, or changes to the way land surfaces exchange energy and water with the atmosphere.
“But as well as taking in carbon dioxide and giving out oxygen, trees emit other gases that take part in complicated chemical reactions in the atmosphere and there are implications for reducing these gases.”
The team evaluated the complex ways in which reactive gases released by forests can impact the climate.
Once in the air, gases released by forests react with other atmospheric chemicals to form minute particles. These particles can reflect sunlight back to space, thereby cooling the climate.
But the reactive gases released by trees can also increase the quantities of methane and ozone– both greenhouse gases which have warming effects on the climate.
The team used a computer model, created at the University of Leeds, to calculate these various warming and cooling effects.
Study co-author Dominick Spracklen, Professor of Biosphere-Atmosphere Interactions: “Scientists have known for a long time that trees emit reactive gases to the atmosphere. But the impact these gases have on the climate has until now not been as widely studied as the effects of carbon dioxide emissions.
“By understanding these complex effects we now know more about how forests are affecting our climate, and we are able to see a clearer picture of the repercussions of deforestation.”
“We found that the cooling impacts of these gases outweigh the warming impacts, meaning that reactive gases given out by forests have an overall cooling effect on our climate.”
The warming and cooling effects of these gases are most closely balanced in the tropics, which is where most deforestation is occurring – suggesting that we really need to understand more about the strength of these impacts.
Dr Catherine Scott, Lead Author