Bill Totten's Weblog

Friday, October 06, 2006

Planet Earth ... but not as we know it

by Mark Lynas

New Statesman (October 09 2006)

You may find it hard to believe, but most environmentalists are optimists. Their doom-monger image is actually the opposite of the truth: their most consistent message is not that we are doomed, but that we have the time and the technology to avoid the worst calamities, if we act now. This insistence on human agency irritates true doom-mongers, such as John Gray, who, reviewing George Monbiot's new book Heat (New Statesman, 18 September), complained: "The assumption that we can stop [global warming] becomes less scientifically tenable by the day, and is in fact not much more than a green version of anthropocentrism". In this, Gray was echoing James Lovelock, who told the New York Times of 12 September that solar panels and wind turbines are "largely gestures", but "no answer at all to the problem" of global warming, which is already essentially out of control.

To environmentalists, this is little short of heresy. But what if Lovelock is right? What if the global warming "tipping point" has already been passed, and escalating "positive feedbacks" indicate that accelerating climate damage is now inevitable? The current scientific consensus suggests that, because of the great thermal inertia of the planetary system, roughly another degree of further warming is already in the pipeline, whatever we do with emissions.

However, no scientific computer modelling study has suggested that irreversible positive feedbacks are already in operation; nor will the next report from the Intergovernmental Panel on Climate Change make such a suggestion. Lovelock's bleaker analysis stems more from a gut feeling than from verifiable data.

Yet this does not mean he should be ignored: Lovelock's Gaia theory - now accepted as the basis for earth system science - was also initially rejected because it differed sharply from the drift of mainstream science. Lovelock's strength is that he eschews reductionism: by analogy, he is a General Practitioner , checking the health of the patient as an entire organism, while most scientists are experts solely in the heart, or lungs or brain.

This is slightly unfair to climate science - the best computer models now integrate almost every aspect of the earth system. Yet I share with Lovelock the suspicion that, far from overemphasising the earth's plight, these models are too conservative. This is not through any unique scientific insight, but because the news coming in suggests that our climate is changing faster than any model simulation yet designed.

Moreover, it is important to remember that there is no single "tipping point" after which it will be too late to save the planet. Rather, there are multiple tipping points for different aspects of the earth system. The biggest Antarctic ice sheets, for example, are stable, and it would take dramatic worldwide warming to melt them. But, for the more fragile Arctic, I suspect the critical threshold has indeed been crossed.

On 14 September Nasa reported that perennial Arctic sea ice had declined by fourteen per cent in a single season between 2004 and 2005: astonishing, and a finding which suggests a flip to an ice-free North Pole is already under way. This will mean open water at the pole within a decade or two, wiping out polar bears and drastically altering northern-hemisphere weather patterns decades sooner than modellers have projected. Because white ice is much more reflective than blue sea, the ice cap also acts as a giant solar mirror. Once it has melted, the planet will absorb more of the sun's heat, giving a boost to global warming.

Recent news of thawing Siberian permafrost is also alarming. On 7 September, researchers reported that five times more methane was leaking from melt-water ponds than had been supposed. Methane is a powerful greenhouse gas. Greenland, too, may have crossed an important line: a Nasa study shows that ice loss from the island has doubled since 2004.

None of these findings, however, tells me to stop campaigning for cuts in greenhouse-gas emissions. Even if the cliff is closer than we thought, it still makes sense to take our collective foot off the accelerator. True, if we're already over the cliff, it may not make much difference - but even just slowing the rate of warming might give wildlife and human civilisation valuable time to adapt, reducing the extent of the mass extinction that is taking place. Yet the fact has to be faced: temperatures are within a degree of their highest levels in a million years, and a new geological era has begun. Whatever we do, a new planet is coming into existence, a planet different from the one we thought we inhabited.

Copyright (c) New Statesman 1913 - 2006

Bill Totten


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