Runaway Global Heating
By Bill Henderson

30 September, 2006

The big global warming story isn't Americans finally accepting an inconvenient truth. Al Gore makes a brilliant presentation, but the big story is the undeniable impact of a severe, early onset, global heating which only paid deniers now refuse to accept. The emerging science story is the risk of this severe impact creating positive feedback which could ratchet up temperatures higher and faster - maybe 10 degrees and more; within decades, not a century away. The forthcoming fourth IPCC report will focus upon ' dangerous global warming'.

Is it possible that the Amazon might die in a third or fourth year of unprecedented drought? Could Los Angeles, St.Louis and Atlanta become as hot as Baghdad in the not too distant future? Could the rapidly melting polar ice sheets raise sea levels so fast that New York, London, Singapore and every other coastal city will have to endure New Orleans style inundation? Collapsing ecosystems, migrating species and disease? A world without polar bears or tigers and maybe soon without people?

Climate change isn't something that will happen in the distant future and increasingly it doesn't look like a gentle warming to which we can adapt.

Newly clear land and sea in polar regions will absorb more heat from sunlight which would have been reflected by ice and new science on 'carbon bombs' strongly suggest that this positive feedback loop is already in operation. The Amazon is a huge carbon sink that unexpectedly could be freed to become greenhouse gas. Melting permafrost, especially in Siberia's yedoma, filling with new lakes, are releasing methane. Beetles and other parasites normally kept in check by very cold winters are killing vast areas of heat stressed temperate and boreal forests; forest fires will help release this carbon into the atmosphere too.

Greenhouse gases from our burning of fossil fuels trap more heat which in turn melts permafrost releasing vast amounts of methane which in turn trap more heat raising temperatures and setting off more carbon bombs - runaway global heating:

Within the next decade or two, Lovelock forecasts, Gaia will hike her thermostat by at least 10 degrees. Earth, he predicts, will be hotter than at any time since the Eocene Age 55 million years ago, when crocodiles swam in the Arctic Ocean.

"There's no realization of how quickly and irreversibly the planet is changing," Lovelock says. "Maybe 200 million people will migrate close to the Arctic and survive this. Even if we took extraordinary steps, it would take the world 1,000 years to recover."
James Lovelock The End of Eden WashPost

The costs today and the range of potential dangers - including the risk of extinction - from global heating suggests that the biggest non-story is the complete lack of informed public debate and the woeful inadequacy of all proposed emission reduction planning. Kyoto, recent Kyoto-style reduction programs, caps and trading, alternative energy development - the use of oil and other fossil fuel use and their contributions of greenhouse gases continue their relentless rise uneffected. Critical decades have been wasted. The problem of path dependence and resulting policy paralysis isn't even a lesson yet learned by climate change experts.

A Draconian change of paths is now clearly necessary and yet impossible. While now accepting human caused global warming, the public still perceives the danger as a moderate increase in temperature requiring shallow, blue box and biking style change.

"Further global warming of 1 C defines a critical threshold. Beyond that we will likely see changes that make Earth a different planet than the one we know." James Hansen

Earth is already as warm as at any time in the last 10,000 years, and is within 1 C of being its hottest for a million years, says Hansen's team. Another decade of business-as-usual carbon emissions will probably make it too late to prevent the ecosystems of the north from triggering runaway climate change, the study concludes (Proceedings of the National Academy of Sciences, vol 103, p 14288).
Fred Pearce New Scientist


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