Greening Of The Planet

By Paul Homewood

 

Satellite data shows the per cent amount that foliage cover has changed around the world from 1982 to 2010.

Credit: Image courtesy of CSIRO Australia

http://www.sciencedaily.com/releases/2013/07/130708103521.htm

 

 

It’s probably been all round the block, but it is worth putting this one up again, for the next time anybody wants to demonise CO2.

This was from a paper from CSIRO last year, Impact of CO2 fertilization on maximum foliage cover across the globe’s warm, arid environments, which shows just how much foliage cover has increased across most parts of the world since 1982.

Science Daily report:

 

Increased levels of carbon dioxide (CO₂) have helped boost green foliage across the world’s arid regions over the past 30 years through a process called CO₂ fertilisation, according to CSIRO research.

In findings based on satellite observations, CSIRO, in collaboration with the Australian National University (ANU), found that this CO₂ fertilisation correlated with an 11 per cent increase in foliage cover from 1982-2010 across parts of the arid areas studied in Australia, North America, the Middle East and Africa, according to CSIRO research scientist, Dr Randall Donohue.

"In Australia, our native vegetation is superbly adapted to surviving in arid environments and it consequently uses water very efficiently," Dr Donohue said. "Australian vegetation seems quite sensitive to CO₂ fertilisation.

This, along with the vast extents of arid landscapes, means Australia featured prominently in our results."

"While a CO₂ effect on foliage response has long been speculated, until now it has been difficult to demonstrate," according to Dr Donohue.

"Our work was able to tease-out the CO₂ fertilisation effect by using mathematical modelling together with satellite data adjusted to take out the observed effects of other influences such as precipitation, air temperature, the amount of light, and land-use changes."

The fertilisation effect occurs where elevated CO₂ enables a leaf during photosynthesis, the process by which green plants convert sunlight into sugar, to extract more carbon from the air or lose less water to the air, or both.

If elevated CO₂ causes the water use of individual leaves to drop, plants in arid environments will respond by increasing their total numbers of leaves. These changes in leaf cover can be detected by satellite, particularly in deserts and savannas where the cover is less complete than in wet locations, according to Dr Donohue.