Two updates on previous stories:

1) We blogged the New Yorker's interview with climate journalist Elizabeth Kolbert. Well, they've now made her outstanding three-part series on climate change available online. It's grim but essential reading -- the best popular writing on the subject I've ever seen:

As best as can be determined, the world is now warmer than it has been at any point in the last two millennia, and, if current trends continue, by the end of the century it will likely be hotter than at any point in the last two million years. In the same way that global warming has gradually ceased to be merely a theory, so, too, its impacts are no longer just hypothetical. Nearly every major glacier in the world is shrinking; those in Glacier National Park are retreating so quickly it has been estimated that they will vanish entirely by 2030. The oceans are becoming not just warmer but more acidic; the difference between day and nighttime temperatures is diminishing; animals are shifting their ranges poleward; and plants are blooming days, and in some cases weeks, earlier than they used to.

The Climate of Man: part one -- Disappearing islands, thawing permafrost, melting polar ice; part two -- The curse of Akkad; part three -- What can be done?

2) We wrote earlier about the possibility of abrupt climate change, the theory that rising temperatures may, paradoxically, trigger a mini-Ice Age -- a theory popularized by the movie The Day After Tomorrow and by a controversial Pentagon study (accompanying interview).

Well, according to the Times, scientists recently found signs that the conditions for such a scenario may, in fact, be unfolding:

Climate change researchers have detected the first signs of a slowdown in the Gulf Stream — the mighty ocean current that keeps Britain and Europe from freezing. They have found that one of the “engines” driving the Gulf Stream — the sinking of supercooled water in the Greenland Sea — has weakened to less than a quarter of its former strength.

The weakening, apparently caused by global warming, could herald big changes in the current over the next few years or decades. Paradoxically, it could lead to Britain and northwestern and Europe undergoing a sharp drop in temperatures.

The always excellent Real Climate krewe has jumped in here to explain that, while very worrying, this doesn't mean New York will turn into a popsicle anytime soon:

It is important to bear in mind that while the changes being seen are indeed significant given the accuracy of modern oceanography, the magnitude of the changes (a few hundredths of a salinity unit) are very much smaller (maybe two orders of magnitude) than the kinds of changes inferred from the paleo data or seen in climate models. Thus while continued monitoring of this key climatic area is clearly warranted, the imminent chilling of the Europe is a ways off yet.

The point here is not merely to follow the ins-and-outs of a somewhat obscure climatological debate. It's to point out that the risks we're running by filling the atmosphere with CO2 are poorly understood even now. The implications of the magnitude of those risks, however, are something we all need to understand, and know in our bones. We live on a new, different planet, and we need new, different thinking if we are, in fact, going to build a future worth living in.

(Best new meme from the New Yorker story? The idea that we have moved out of the Holocene and now find ourselves in the "Anthropocene" -- "This new age is defined by one creature—man—who had become so dominant that he was capable of altering the planet on a geological scale.")

The article proposing the anthropocene is available online at:
http://www.mpch-mainz.mpg.de/~air/anthropocene/Text.html

From the article:

The expansion of mankind, both in numbers and per capita exploitation of Earth's resources has been astounding (5). To give a few examples: During the past 3 centuries human population increased tenfold to 6000 million, accompanied e.g. by a growth in cattle population to 1400 million (6) (about one cow per average size family). Urbanisation has even increased tenfold in the past century. In a few generations mankind is exhausting the fossil fuels that were generated over several hundred million years. The release of S02, globally about 160 Tg/year to the atmosphere by coal and oil burning, is at least two times larger than the sum of all natural emissions, occurring mainly as marine dimethyl-sulfide from the oceans (7); from Vitousek et al. (8) we learn that 30-50% of the land surface has been transformed by human action; more nitrogen is now fixed synthetically and applied as fertilizers in agriculture than fixed naturally in all terrestrial ecosystems; the escape into the atmosphere of NO from fossil fuel and biomass combustion likewise is larger than the natural inputs, giving rise to photochemical ozone ('smog') formation in extensive regions of the world; more than half of all accessible fresh water is used by mankind; human activity has increased the species extinction rate by thousand to ten thousand fold in the tropical rain forests (9) and several climatically important "greenhouse' gases have substantially increased in the atmosphere: CO2 by more than 30% and CH4 by even more than 100%. Furthermore, mankind releases many toxic substances in the environment and even some, the chlorofluorocarbon gases, which are not toxic at all, but which nevertheless have led to the Antarctic 'ozone hole' and which would have destroyed much of the ozone layer if no international regulatory measures to end their production had been taken. Coastal wetlands are also affected by humans, having resulted in the loss of 50% of the world's mangroves. Finally, mechanized human predation ("fisheries') removes more than 25% of the primary production of the oceans in the upwelling regions and 35% in the temperate continental shelf regions (10). Anthropogenic effects are also well illustrated by the history of biotic communities that leave remains in lake sediments. The effects documented include modification of the geochemical cycle in large freshwater systems and occur in systems remote from primary sources (11-13).

Posted by: Garry Peterson on June 1, 2005 1:39 PM

OK, an excellent concise review of the situation which can only be turned around [or at least ameliorated] by the most powerful, intelligent, committed leadership by the United States. This is not to overemphasize our importance but the fact of the size of our economy, our example by use of 25% of the world's energy with 4% of the world's population, means that no solution is conceivable with out our total commitment to change.
So how do we achieve that?
The science is in. The beginnings of global warming have commenced. Repeated explanations, vivid depictions, dire warnings have not awakened the public. We are silly tree huggers or dangerous eco-terrorists, we prefer snail darters to people and jobs. And EXXON, Haliburton etc continue to direct the government they paid for.
How can we effect change?

Posted by: jim worth on June 8, 2005 12:16 PM