Climate change could be 'irreversible' for 1,000 years? Gulp!

In short, if CO2 concentrations peak at 450-600 ppm, declines in rainfall during the dry season in regions such as the US Southwest or the Mediterranean are comparable to the Dust Bowl drought in the US during the 1930s and those seasonal declines persist for millenniums. Sea level from heat expansion alone rises by an average of up to three feet through the year 3000.

For simplicity's sake, they didn't take a large number of secondary effects into account. And projections of melting of Greenland's and Antarctica's ice caps are still too uncertain to include. The levels Solomon's team projected are a minimum, based on better-understood physical processes. The results appear in the issue of the Proceedings of the National Academy of Sciences for the week of Jan. 26, 2009.

Records of past climate regimes over tens of millions of years or more and the geophysical processes involved, such as those Dr. Archer explores in his book, certainly add weight to the way Solomon and her colleagues have framing the global warming issue in terms of irreversibility.

Long-term change v. public perceptions

But as calls to action, some analysts wonder if that's enough to galvanize the public.

When pollsters ask about global warming as a stand-alone issue, in some surveys people tend to say it's serious and requires action. Some have even responded that they'd even pay higher energy costs if that helped underwrite the move to more climate-friendly ways to meet energy needs.

But ask people to stack global warming against other issues, and it falls to the bottom of a long list. It remains a concern. But it does not enjoy a level of urgency that many environmental groups and scientists see.

In a poll published Jan. 22 and conducted by the Pew Research Center for People and the Press, out of 1,503 respondents, 85 percent pointed to the economy as a top priority; 30 percent said global warming was a top priority.

To some extent, this isn't surprising. One can find similar patterns in responses when people are asked about space exploration and the US space program.

Over at Framing Science, American University communications professor Matt Nesbit has this to say about what the Pew survey results imply for using charismatic animals, or geographically and temporally remote effects to build a case for action on global warming:

It's ... time to stop focusing narrowly on remote polar impacts, looming environmental disaster, or symbols such as polar bears. These exemplars are either not personally relevant enough to most audiences, are dismissed as remote and far off in the future, or easily re-framed as "alarmism" sending interpretations back into the mental box of lingering scientific uncertainty.

Stand by for a forthcoming paper that details some of the possible alternatives, he adds.

Whatever its role may or may not be as yet another in a long list of calls to arms on climate change, the paper could have some immediate implications for policy, the team suggests.

Some the economic analysts have posited that it's better to back off of quick action and wait for the technology to come along that will scrub the air of excess CO2 in short order and at a time when economic growth will ensure that more countries can afford the technologies needed. But as the team points out, excess CO2 is not a short-lived air pollutant such as ozone or sulfur-dioxide. Once it's in the air, there's no going back -- short of so-far unproven approaches for scrubbing CO2 from the air, especially at the scale needed.

In addition, the Kyoto Protocol approach of throwing all human-generated greenhouse gases into a pot and allowing countries to pick the easiest ones to deal with to meet their emissions targets may help slow temperature increases in the short to medium term. But controls on these shorter-lived gases do nothing to ease the millennial-scale effects.

To which one might add one more policy implication: A need to put the pedal to the metal on increasing adaptation planning efforts in developed countries as well as increasing adaptation help for developing countries. Adaptation is no substitute for emissions reductions. But if the somber song of Solomon et al is correct, the need for some degree of adaptation measures is as inevitable as the changes she and her colleagues see humans imposing on climate.

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