A tipping point on global warming?

Posted by Matthew Wheeland at 3:12 PM on March 27, 2006.

For many, many weeks I've started and then stopped writing a blog post just like this. Something keyed off the latest news that last year was the hottest on record (or equally troubling, that the top five warmest years since 1890 occured in the last seven years), or the global increase in devastating hurricanes and cyclones, or that we may not be able to reverse rising sea levels, or that the next century will likely bring widespread wars over scarce resources.

But I always hesitated to post these stories. Partly it's because of my long-held belief that at this point in time, climate change is as much an article of faith as it is a scientific reality. If you accept the fact of climate change, you already know about these details. If you refuse to believe that humans are the cause of rapid (and possibly irreversible) global warming, then your head is buried so far deep in the sand that no number of factoids is going to change your mind.

So I'm pleased to say that, as with so many of the most pressing problems facing the country and the world, most Americans are in agreement, and it's a small minority of exceedingly vocal deniers who are serving as roadblocks to progress.

The cover story in this week's Time Magazine paints a dire picture of our global reality, but at the same time a new poll offers some profound encouragement. Jeffrey Kluger writes:

Even as nature crosses its tipping points, the public seems to have reached its own. For years, popular skepticism about climatological science stood in the way of addressing the problem, but the naysayers--many of whom were on the payroll of energy companies--have become an increasingly marginalized breed. In a new TIME/ ABC News/ Stanford University poll, 85 percent of respondents agree that global warming probably is happening. Moreover, most respondents say they want some action taken. Of those polled, 87 percent believe the government should either encourage or require lowering of power-plant emissions, and 85 percent think something should be done to get cars to use less gasoline.

This is the moment that I've been waiting for, some acknowledgement that it is a vocal minority that gives such out-of-proportion weight to the argument that this dire situation is nothing more than the Earth's natural climatic cycle. But with the good news often comes the bad. While we may have reached some kind of momentum for humankind, or at least for Americans (long the global laggards on this issue), but the planet is also revving up its own tipping point: Kluger points out the beginning of two very worrisome feedback loops at the Earth's poles show we may have indeed reached a point of no return on global warming:

One of the reasons the loss of the planet's ice cover is accelerating is that as the poles' bright white surface shrinks, it changes the relationship of Earth and the sun. Polar ice is so reflective that 90 percent of the sunlight that strikes it simply bounces back into space, taking much of its energy with it. Ocean water does just the opposite, absorbing 90 percent of the energy it receives. The more energy it retains, the warmer it gets, with the result that each mile of ice that melts vanishes faster than the mile that preceded it. [...]

A similar feedback loop is melting permafrost, usually defined as land that has been continuously frozen for two years or more. There's a lot of earthly real estate that qualifies, and much of it has been frozen much longer than two years--since the end of the last ice age, or at least 8,000 years ago. Sealed inside that cryonic time capsule are layers of partially decayed organic matter, rich in carbon. In high-altitude regions of Alaska, Canada and Siberia, the soil is warming and decomposing, releasing gases that will turn into methane and CO2. That, in turn, could lead to more warming and permafrost thaw, says research scientist David Lawrence of the National Center for Atmospheric Research (NCAR) in Boulder, Colo. And how much carbon is socked away in Arctic soils? Lawrence puts the figure at 200 gigatons to 800 gigatons. The total human carbon output is only 7 gigatons a year.

Clearly, we are not out of the woods yet. But because the vast majority of us have woken up to the fact that we are in the woods, and that there's a clear path out of the woods (courtesy of hard-working groups like Sierra Club, Natural Resources Defense Council, Greenpeace and Rainforest Action Network), is a major improvement and gives me, at last, cause for hope.

Matthew Wheeland is AlterNet's managing editor.