PLEA Network

20 February 2016, Climate News Network, Carbon rise keeps water in drylands. Increased carbon dioxide in the atmosphere because of climate change is helping to turn the world’s drylands a more luxuriant green − but that’s not necessarily good news. The drylands of the world are getting greener, and researchers think it is thanks to higher levels of carbon dioxide in the atmosphere. In a paradoxical discovery, even as landscapes become increasingly at risk of desertification, they may also look more luxuriant. Two scientists from Purdue University in Indiana, US, and a researcher in Saudi Arabia report in the journal Scientific Reports that they analysed 45 satellite studies from eight countries to confirm that the drylands of the world are responding to global warming and climate change by getting greener.Their conclusion is that rising levels of the greenhouse gas that is warming the planet – a consequence of humans’ combustion of fossil fuels over the last two centuries – are also delivering extra fertilisation to plants, so that photosynthesis can function with less water. In turn, this means that more soil water stays in the ground. Negative feedback “We know from satellite observations that vegetation is greener than it was in the past,” says Lixin Wang, an Earth scientist from Purdue, and one of the authors of the report. “We now understand why that is occurring, but we don’t necessarily know if it is a good thing or not.” The observation seems to suggest that nature is delivering what engineers call negative feedback: as the Earth warms because of the rising greenhouse gas levels, so vegetation is responding to grow more vigorously and soak up more carbon. This has been observed before, but it may not be a good thing because one consequence of climate change is that drylands everywhere – and they are home to around two billion people – are likely to become increasingly parched, with cruel consequences for the world’s poorest people who make up most of those two billion. Nor is it certain that all drylands will respond with more vigorous growth. For some terrains, ecological devastation could increase. Read More here