A short excerpt from a talk by James Hansen at this year’s AGU meeting is in the The New York Review of Books (53:1):

The Earth’s climate is nearing, but has not passed, a tipping point beyond which it will be impossible to avoid climate change with far-ranging undesirable consequences. These include not only the loss of the Arctic as we know it, with all that implies for wildlife and indigenous peoples, but losses on a much vaster scale due to rising seas.

Ocean levels will increase slowly at first, as losses at the fringes of Greenland and Antarctica due to accelerating ice streams are nearly balanced by increased snowfall and ice sheet thickening in the ice sheet interiors.

But as Greenland and West Antarctic ice is softened and lubricated by meltwater, and as buttressing ice shelves disappear because of a warming ocean, the balance will tip toward the rapid disintegration of ice sheets.

The Earth’s history suggests that with warming of two to three degrees, the new sea level will include not only most of the ice from Greenland and West Antarctica, but a portion of East Antarctica, raising the sea level by twenty-five meters, or eighty feet. Within a century, coastal dwellers will be faced with irregular flooding associated with storms. They will have to continually rebuild above a transient water level.

This grim scenario can be halted if the growth of greenhouse gas emissions is slowed in the first quarter of this century.

—From a presentation to the American Geophysical Union, December 6, 2005

In the same issue Bill McKibben has a related article, The Coming Meltdown, about climate change and recent popular books on climate change, including Mark Bowen’s Thin Ice.

McKibben writes about James Hansen’s 1988 congressional testimony on climate change, and describes the scientific response to scientific realization of the likliehood of anthropogenic climate change

Science, on the other hand, both rose to the occasion and failed badly. The world’s climatologists organized themselves into the Intergovernmental Panel on Climate Change, or IPCC, in those heady months of 1988. With large government funding that was partly made available because of Hansen’s warnings, the panels of experts soon had a vast collection of studies and computer models to pore over. And though the IPCC’s procedures were byzantine—they relied, Bowen writes, on “a peer review process…incalculably more cumbersome than anything ever applied to a scientific issue before”—the group eventually managed to reach a potent conclusion. By 1995, the IPCC was ready to conclude that “the balance of evidence suggests that there is a discernible human influence on global climate.” This result was remarkable: more than a thousand scientists, working through a process that allowed much political input from governments concerned to deny global warming, nonetheless found the evidence so overwhelming that they were able to state that one species, ours, was now changing pretty much everything on the face of the planet.

But at the same time, the conclusions were watered down and over-hedged, playing at least as much into the hands of the few remaining skeptics, who seized on every possible opportunity to dampen public concern. The scientific method, pursued in this fashion, seemed unequal to the gravity of the task at hand. Bowen writes, “I believe it is fair to say that serious scientific debate about the existence and potential danger of human-induced global warming died with that statement.” That is true—but it’s also true that it contributed remarkably little to the larger public debate, especially in the US. And that’s a failure for which scientists bear some of the blame.

Bowen quotes Hansen:

The scientific method does require that you continually question the conclusions that you draw and put caveats on the conclusion—but that can be misleading to the public. It seems to me that when we talk to the public we have to try to give a summary. And it’s not easy for most scientists to do—and not easy for me.
Clearly, for the mild-mannered Hansen, who has no taste for public controversy, it was not easy. But he did it. And for that, as well as for his original scientific work, he deserves not only enormous credit but also, I would suggest, the Nobel Prize, perhaps the first joint Chemistry-Peace award.

The Jan9, 2006 New Yorker also has an article, by Elizabeth Kolbert who wrote the climate of man series (and a forthcoming book on climate change), on the evolutionary and population response of plants and animals to current climate change, but it is not online.