October 31, 2008

Jim Hansen's Tipping Point

The foregoing chart from the International Panel on Climate Change, which shared the Nobel Prize with Al Gore in 2007, shows the dimensions of the warming problem under three different scenarios: mild, hot, and extra spicy.

This chart is from the IPCC's 2007 presentation to policy-makers of the science behind global warming, which urged upon them the gravity of the situation.

The specter of global warming, and the disastrous climatic effects that might ensue from it, has waxed and waned in public consciousness over the past two decades. It was only in 1988 that an obscure NASA scientist named Jim Hansen brought the prospect of global warming to widespread attention, in testimony before Congress. The message was not popular then--"The American way of life is not up for negotiation," declared the first President Bush. As a way of declaring its indifference, Congress rejected carbon taxes in 1993. But anxiety has heightened dramatically in recent years as the scientific evidence has accumulated.

In a recent paper, Hansen's conclusion, with other colleagues, "is that, if humanity wishes to preserve a planet similar to the one on which civilization developed and to which life on Earth is adapted, CO2 must be reduced from its present 385 ppm (parts per million) to, at most, 350 ppm."

350.org has made this a rallying cry.

It is an extremely tall order, as Hansen acknowledges: just to keep Co2 at 425 ppm, assuming plentiful oil and gas, coal use must be phased out by 2030 unless a means is found of "capturing and sequestering" the CO2 emissions it produces. Unconventional sources of fossil fuels like tar sands or shale oil could also not be developed on any appreciable scale if the target were to be met. Hansen also calls for an immediate moratorium on coal-fired power plants and constraints on oil extraction on "public lands, off-shore regions under government control, environmentally pristine regions and extreme environments."

Time is running out, writes Bill McKibben. A change of course is urgent. That "means no more new coal-fired power plants anywhere, and plans to quickly close the ones already in operation. (Coal-fired power plants operating the way they're supposed to are, in global warming terms, as dangerous as nuclear plants melting down.) It means making car factories turn out efficient hybrids next year, just the way we made them turn out tanks in six months at the start of World War II. It means making trains an absolute priority and planes a taboo. . . . it means the rich countries of the world sharing resources and technology freely with the poorest ones, so that they can develop dignified lives without burning their cheap coal."

Lots of questions may be raised about this perspective. Is it remotely feasible? What is the cost? Assuming it is the right objective, what prospects are there for a domestic reconsideration of our profligate ways or for international collaboration that goes well beyond the Kyoto Protocol?

No realistic accounting can ignore the profound obstacles that stand athwart attempts to lower the level of CO2 in the atmosphere. The gap in perspective between the developed world, and especially the United States, which seeks to preserve its "energy-intensive lifestyle," and the developing world, which refuses to be condemned to 1/10th the per capita consumption of the rich countries, constitutes a huge obstacle to any consensus agreement.

If the Cassandras are right, we have an enormous challenge and a profound moral responsibility to adjust our course so as not to visit upon future generations the ill consequences foreseen. But given the way of the world, the likelihood of this adjustment is remote. "A long-term overshoot of the 350 ppm target level, with potentially disastrous consequences," Hansen notes, is "a near certainty if the world stays on its business-as-usual course."

What would knock the world off its rocker? Is the idea of future devastating consequences, in a sort of great hereafter, sufficient to change its "business-as-usual course"? Will Asia consent? Will China and Russia and Brazil and India consent? Can America offer an attractive bargain to them? What would that be?

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