Trees may not contribute to global warming as much as once believed, according to a new study. The lifeforms were found to adapt to global warming significantly faster than predictions had assumed.
Plants and microbes in soil release carbon dioxide as part of their life processes, totaling 120 billion tons each year. This is around six times the amount injected by human beings through the burning of fossil fuels. Environmentalists were concerned that these emissions of greenhouse gases could significantly impact global climate change.
Photosynthesis absorbs slightly more carbon dioxide worldwide than is released through respiration. Normally, this difference allows plants to take in approximately 30 percent of the greenhouse gases produced by industries, power plants and vehicles. However, as temperatures start to rise, the amount of carbon dioxide released to the atmosphere climbs, while intake remains the same.
Researchers assembled 1,200 trees in a heated outdoor area, in order to determine how the ratio of intake and respiration in trees is affected by rising temperatures.
During climate talks held in Paris, France at the end of 2015, nations around the world agreed to limit global temperature rise to 3.6 degrees Fahrenheit by the end of the 21st Century.
Climate models used in studies assume changes in the release of carbon dioxide by plants, trees and soil microbes "increases over the long-term the same way it does over the course of a few hours," said Peter Reich of the University of Minnesota.
A shift in the ratio of respiration to intake measuring just 3 percent, driven by rising temperatures, was predicted be enough to turn carbon sinks into carbon sources, fueling further climate change. However, the experiment showed that all 10 species of trees examined adapted to warmer conditions. Instead of releasing 23 percent more carbon, respiration increased just 5 percent.
However, carbon can still be released to the air when trees are cut down or burned. The area of woodlands lost to deforestation in the last 25 years is twice the size of France, according to researchers. This is due, largely, to urbanization and agricultural purposes.
Analysis of the contribution of plants to greenhouse gas emissions was profiled in the journal Nature.
Image: Miguel Vieera | Flickr
