Plants may absorb more carbon dioxide than previously thought

By Simon Levey - Thursday 22 March 2012 - The capacity of terrestrial ecosystems to absorb carbon dioxide emissions from human activity may be greater than previously thought, according to a new study published in Nature Climate Change , which looks at how plants react to environmental change. The authors say these results improve our ability to look into the planet's future and predict the magnitude of climate change before it happens. The scientists from Imperial College London and University of York were investigating how changes in temperature and atmospheric carbon dioxide levels - such as those predicted under the effects of global climate change - affect soil respiration and a plant's rate of growth, photosynthesis and respiration. The research addresses a key question in environmental science about whether an increase in global temperatures will cause an increase or a decrease in the ability of ecosystems to absorb carbon dioxide from the atmosphere, a problem for which scientists do not yet have a convincing answer. Some scientists have suggested that increases in temperature will cause the release of greenhouse gases from ecosystems such as oceans and soils, possibly resulting in 'runaway' climate change, where environmental change passes a tipping point and exacerbates its own effects. Others have suggested that an explosive growth of plants and algae will help to mop up excess carbon dioxide from the atmosphere. Following the results of this study, the scientists conclude that, with the help of plants, the Earth's terrestrial ecosystems may well have more capacity to buffer against 'runaway' climate change than scientists previously thought.