Jumat, 29 Juni 2012

Africa's savannahs may all change into forests before the turn of the century due to excess CO2 in the atmosphere

Africa's savannahs may all change into forests before the turn of the century due to excess CO2 in the atmosphere

By Eddie Wrenn

PUBLISHED: 06:55 EST, 29 June 2012 | UPDATED: 07:26 EST, 29 June 2012

A study suggests that some of Africa's savannahs - large areas sparse vegetation other than grass - may become forests by the end of the century.

Research from The Biodiversity and Climate Research Centre and the Goethe University Frankfurt suggests that a build-up of carbon dioxide in the soil will force an increase of tree cover throughout Africa.

When CO2 in the air and soil reaches a certain density, it forces trees to increase their size and foliage, meaning the open-sky savannahs may end up with a tree canopy.

The savannahs may change to forests within 100 years, according to new research which believes CO2 may lead to rapid tree growth

The savannahs may change to forests within 100 years, according to new research which believes CO2 may lead to rapid tree growth

Because each site has an individual 'threshold', it is likely that separate savannahs will begin to change at different times, by many of them will switch before 2100, according to the researchers.

According to Science Daily, experimental studies show that plants do not show a large response to CO2 fertilisation.

But Steven Higgins, lead author of the study, said: 'Most of these studies were conducted in northern ecosystems or on commercially important species.

The savannahs of Africa are generally grassland with some trees - but they may be forests within 100 years

The savannahs of Africa are generally grassland with some trees - but they may be forests within 100 years

'In fact, only one experimental study has investigated how savanna plants will respond to changing CO2 concentrations and this study showed that savanna trees were essentially CO2 starved under pre-industrial CO2 concentrations, and that their growth really starts taking off at the CO2 concentrations we are currently experiencing.'

Some theorists call this abrupt switch a 'catastrophic regime shift', where a big switchover happens rapidly. These are normally caused by small changes in the area's regulation systems, but the small changes have a 'butterfly effect', where large-scale processes are set into motion.

The study found that locations where the temperature rise associated with climate change occurs rapidly, for example in the center of southern Africa, will switch to forests later as there is a high rate of temperature increase, which means the savanna grasses can remain competitive for longer.

This means that areas will adjust over differing time-scales, which will reduce shocks to the biosphere. While the changes will be a 'catastrophic regime change' for the area,  when the change is averaged over the area, it will be smoother and more gradual..

Higgins said: 'While this may seem reassuring, we have to bear in mind tha t these changes are still rapid when viewed on geological time scales.'

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Agree with spectatpr@14:01 Whoever "adapted" this article from the original paper hasn't got a clue about science at all. Then again it is on the DM website so I suppose that shouldn't come as any great suprise.

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Excellent. Then they can stop bleating about the rain forests. - David Wight, Carrickfergus, 29/6/2012 14:45 You seem to be the only one bleating!

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The thing about "experts" is that whatever the subject, they have no more idea than the rest of us about what will happen. The only difference is they get lots of money for their predictions.

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Far too often there is too much emphasis on the 'bad' that CO2 can do to the world when, in reality, the GOOD far outweighs it. More greenery, more productive crops, fewer deaths from cold etc etc. The scaremongers are actually scared themselves that this self-evident truth will destroy their cause hence the lack of promotion of these CO2 benefits.

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Well, the fact that CO2 is 'plantfood' is of course well known. On youtube you can see this searching for 'seeing is believing', in the Netherlands they inject CO2 into glasshouses to increase crop output. You can also see this looking at the fotosynthesis reaction (CO2 + H2O and light). CO2 is the best gas on earth. We would all die without it, since plants would die. The amount of CO2 in the atmosphere is now around 400, which was 180 during the last iceage (during colder periods CO2 is absorbed by the oceans). Under 150 most plants will suffocate, so we were very close to that point, just before the farao's.

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Wait, I thought deforestation was one of the causes of "man-made" global climate change. Now excess trees are a result of "man-made" global climate change? I'm confused.

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CO2 forces trees to increase size and foliage? Since increased size and foliage is an evolutionary advantage the term "force" doesn't even begin to describe the process at work here even if I try not to split hairs... It's like saying a bank robber forced a million pounds into a bank vault.

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Excellent. Then they can stop bleating about the rain forests.

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The reason why Africa did not become a forested area for the past 5000 years is because there is a lack of water. I don't see this changing for the next few thousand years.

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This is the worst junk-science article I have ever read; this journalist does not appear to understand even the most BASIC ideas about gases, ecology, trees or climate. I would try to add corrective comments but I would literally have to re-write the entire piece of garbage.

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