Saturday, 30 June 2012

Sensational study: Global warming turning Africa´s savannahs into green forests

This barren savannah could soon be a green forest

Great news for Africa: Forget all the tree planting, global warming will turn the continent´s barren savannahs into green forests, according to a new German study, published in the journal Nature

New research from researchers based at two German research institutes predicts that large parts of Africa's savannahs may well be forests by the time the year 2100 comes round. 

Writing in the journal Nature, Steven Higgins from the Goethe University Frankfurt and Simon Scheiter from the Biodiversity and Climate Research Centre (BiK-F) in Frankfurt suggest that fertilisation by atmospheric carbon dioxide (CO2) is leading to major increases in tree cover throughout Africa. 

Grasses and trees differ fundamentally in their response to temperature, CO2 supply and fire, and continually struggle for dominance in savannahs. 

Previously, these shifts in dominance have taken place over long periods of time, but the current wave of atmospheric changes has sped up rates of change. 
Once a critical threshold of CO2 concentration is exceeded, savannahs become less grassy and more forest-like. However, each savannah has its own critical threshold which means that each savannah will make the switch at different times. This helps reduce the risk of a simultaneous and dramatic change emanating from the savannahs.  

The new findings should of course apply to other savannah type areas in the world as well, which makes a warmer future all the more welcome! 


selsey.steve said...

Savannahs come and savannahs go.
It's called Nature.

Doug Proctor said...

I live in the dry temperate area of Alberta, next to the equally dry temperate area of Saskatchewan known as the prairies. The grasslands there may have been started by climate (I doubt) but they were sustained by wildfires. Once the land was broken up by farming, and roads were established, wildfires of large consequence ended. And the trees sprouted like weeds. Now, of course, you have to get county permission to bulldoze or burn down the brush on your property, because they and the deer in them are "natural". Natural until 1935 or so: my father-in-law remembers the only tree that existed for twenty miles when he was a kid, and the first deer they saw (deer need the brush).

I wonder if savannah turning into forest has to do with changes in grazing animals, though. All the brush you have now can be eliminated in a few years simply by putting cattle into the fields. The cattle trample the young growth as they seek shade. My belief is that bison created the prairies in the first place, which then was stabilized by the wildfires.

So African savannahs: not climate change but grazer change, then loss of wildfires.