Tuesday, 4 June 2013

Growing emissions of CO2 accelerated greening of arid areas around the globe

The Australian Commonwealth Scientific and Industrial Research Organisation (CSIRO), established the Environmental Earth Observation Research Program, to conduct, among the others, research activities to assess impacts of climate change on vegetation functioning and processes. A recent study presented by research leader Randall Donhue at CSIRO showed how the greening of large stretches of arid land observed by satellite images since the 1980s is associated to the rising concentrations of carbon dioxide (CO2), which fertilizes plant growth. CO2 is also a major player in global climate change, which is making the planet warmer and, in places, wetter. Warmer temperatures in cold regions and increasing precipitation in dry areas are therefore expected to spur plant growth.
The picture below analyses the greening of the Sahel as observed from satellite images for the period 1982-2003. The overall trend is positive over a large portion of the Sahel region, reaching up to 50 per cent increase in parts of Mali, Mauritania and Chad, and confirming previous findings at a regional scale.

As the study by CSIRO noted, increases in CO2 also fertilize plant growth by making more carbon available to plants and allowing plants to lose less water to the air during the process of photosynthesis. Plants need carbon and water for growth. More of both, means more growth. In particular, the greening effect of increased CO2 proved at global level is even seen in areas that are getting drier due to reduced rainfall and warmer temperatures as a result of global climate change. The results of this study give evidence to new elements for the better understanding of the global warming phenomenon.