Another hard-luck story: Climate Change, the Amazon and the Arctic
In yesterday’s Guardian there is yet “another hard-luck story that you’re gonna hear”:
“Chris Jones, who led the research, told the conference: “A temperature rise of anything over 1C commits you to some future loss of Amazon forest. Even the commonly quoted 2C target already commits us to 20-40% loss. On any kind of pragmatic timescale, I think we should see loss of the Amazon forest as irreversible.” Peter Cox, professor of climate system dynamics at the University of Exeter, said the effects would be felt around the world. “Ecologically it would be a catastrophe and it would be taking a huge chance with our own climate. The tropics are drivers of the world’s weather systems and killing the Amazon is likely to change them forever. We don’t know exactly what would happen but we could expect more extreme weather.”
Massive Amazon loss would also amplify global warming “significantly” he said. “Destroying the Amazon would also turn what is a significant carbon sink into a significant source.””
Just a few days ago new results came out about the loss of arctic ice showing once again that predictions are continuously shown to be way too conservative – positive feedback loops are upon us:
“Amazon dieback is one of the key positive feedbacks brought about by global warming. These are typically runaway processes in which global temperature rises lead to further releases of CO², which in turn brings about more global warming. In the Amazon this happens on a more localised scale but the result, increased forest death, also releases carbon into the atmosphere.
Experts predict that higher worldwide temperatures will reduce rainfall in the Amazon region, which will cause widespread local drought. With less water and tree growth, “homegrown” rainfall produced by the forest will reduce as well, as it depends on water passed into the atmosphere above the forests by the trees. The cycle continues, with even less rain causing more drought, and so on.
With no water, the root systems collapse and the trees fall over. The parched forest becomes tinderbox dry and more susceptible to fire, which can spread to destroy the still-healthy patches of forest.
Other positive feedback effects expected by scientists, are releases of carbon stored in frozen arctic ecosystems and an increase in the sun’s energy absorbed by the planet as ice melts.”
As already mentioned above, new results from the ice front have arrived and the predictions for an ice free Arctic summer is not far in the future:
“The year “2013 is starting to look as though it is a lot more reasonable as a prediction. But each year we’ve been wrong — each year we’re finding that it’s a little bit faster than expected,” he told Reuters.
The Arctic is warming at twice the rate of the rest of the world and the sea ice cover shrank to a record low in 2007 before growing slightly in 2008.
In 2004 a major international panel forecast the cover could vanish by 2100. Last December, some experts said the summer ice could go in the next 10 or 20 years.
If the ice cover disappears, it could have major consequences. Shipping companies are already musing about short cuts through the Arctic, which also contains enormous reserves of oil and natural gas.”
It’s not looking good.
