One of the unexpected consequence of higher CO2 levels, is an apparent revival of arborescence in the deserts of the world.
Here and there, in the Sahara and other deserts, trees are starting to grow again from sand.
Between 1982 and 2010, plant and leaf cover has grown by 11% worldwide, in places such as the United States southwest, the Outback of Australia, and in parts of Africa.
Scientists had long suspected that higher CO2 levels would spur arborescence, or plant growth. In fact, during the warmer periods of the earth, vegetation was much more prevalent than in cold, or low CO2, eras.
CO2 is an important catalyst of photosynthesis. The more CO2, the more vegetation can live.
Another reason is also the increased rate of rainfall.
Scientists have concentrated on the study of desert plants to see which factor, rainfall, CO2 or temperature change alone has caused the spurt in tree growth.
After careful observation of desert areas, they determined that the most important factor in the sudden growth is carbon dioxide.
What is more important however, is the fact that CO2 acts as a 'fertilizer', in the sense that it shifts the types of vegetation in different areas, so that "trees are reinvading grasslands, and this could quite possibly be related to the carbon dioxide effect," said Prof. Donohue of the Commonwealth Scientific and Industrial Research Organization, "Long lived woody plants are deeply rooted and are likely to benefit more than grasses from an increase in carbon dioxide."
However, it's not all good news: CO2 levels also change the rainfall patterns, which in turn could counteract the positive effects of additional carbon dioxide.
Source : LiveScience 6.3.13
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