Dr. James Hansen: We Are Now Approaching the Global Warming Tipping Point

by Damozel | Dr. James Hansen [bio], who gave testimony before Congress today 20 years after his first presentation, has some sobering words for those who think concerns about the environment can wait while we sort out gas prices. The potential for harm that may result from failure to address these concerns is so overwhelming that many people still can't bring themselves to see itself as the gravest issue now confronting the world.  The time when denial is still possible may not last long.

According to Dr. Hansen, we have now used up any slack we may have had.  Prevention is --- 'barely' --- still possible.  Emphasis on 'barely.'

[A] wide gap has developed between what is understood about global warming by the relevant scientific community and what is known by policymakers and the public. Now, as then, frank assessment of scientific data yields conclusions that are shocking to the body politic. Now, as then, I can assert that these conclusions have a certainty exceeding 99 percent. [continue]

 The next president and Congress must define a course next year in which the United States exerts leadership commensurate with our responsibility for the present dangerous situation. 

Otherwise it will become impractical to constrain atmospheric carbon dioxide, the greenhouse gas produced in burning fossil fuels, to a level that prevents the climate system from passing tipping points that lead to disastrous climate changes that spiral dynamically out of humanity's control.  (HuffPost)

What's at stake?  Hansen explains: 

[C]limate is nearing dangerous tipping points. Elements of a "perfect storm," a global cataclysm, are assembled.

  Climate can reach points such that amplifying feedbacks spur large rapid changes. Arctic sea ice is a current example. Global warming initiated sea ice melt, exposing darker ocean that absorbs more sunlight, melting more ice. As a result, without any additional greenhouse gases, the Arctic soon will be ice-free in the summer.  

More ominous tipping points loom. West Antarctic and Greenland ice sheets are vulnerable to even small additional warming. These two-mile-thick behemoths respond slowly at first, but if disintegration gets well under way, it will become unstoppable....Hundreds of millions of people would become refugees, and no stable shoreline would be reestablished in any time frame that humanity can conceive.

  Animal and plant species are already being stressed by climate change. Species can migrate in response to movement of their climatic zone, but some species in polar and alpine regions will be pushed off the planet. As climate zones move farther and faster, climate change will become the primary cause of species extinction. The tipping point for life on the planet will occur when so many interdependent species are lost that ecosystems collapse.  (Read more at Huff Post)

This is a lengthy and alarming article.  I recommend it.
 

More discussion available at memeorandum

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Comments

[Adam]

Another major "tipping point" factor not mentioned in that article is the enormous quantity of greenhouse gasses currently trapped in permafrost in northern Russia and Canada. Higher temperatures could release these gasses, contributing to runaway warming. Here's a good article on that subject:

http://www.commondreams.org/headlines06/0907-07.htm

I don't think anyone can say with a high degree of confidence how near we are to a tipping point of runaway global warming. There's an enormous number of variables involved, and predictive models disagree about when things really move beyond our ability to stop them. But the fact is, we MIGHT be near the tipping point, and that really ought to be enough to spur serious action.

The "wide gap... between what is understood about global warming by the relevant scientific community and what is known by policymakers and the public" is owed to the MASSIVE disinformation campaign which has been waged by those who stand to lose profit margin if we act to reduce global warming. That, combined with many people's willingness to believe a convenient lie over an inconvenient truth.

There's a remarkable parallel between the tactics "global warming skeptics" (read: disinformation outfits) have used, and the tactics the tobacco compaines used as the evidence of the cancer link grew more and more undeniable. It's almost as if somebody happened upon their playbook. (First, deny the existance of the data. Then, deny the causative link. Then, lobby to slow legislation and create legal obstacles...)