Naturally Interesting

James Hansen, one of the world’s leading climate scientists, will today call for the chief executives of large fossil fuel companies to be put on trial for high crimes against humanity and nature, accusing them of actively spreading doubt about global warming in the same way that tobacco companies blurred the links between smoking and cancer.

Seen here.

A while back James Hansen, chief climatologist at NASA’s Goddard Institute for Space Studies, published a paper Target Atmospheric CO2: Where should humanity aim? I finally got around to reading it, you should too.

Decreasing CO2 was the main cause of a cooling trend that began 50 million years ago, large scale glaciation occurring when CO2 fell to 425±75 ppm, a level that will be exceeded within decades, barring prompt policy changes. If humanity wishes to preserve a planet similar to that on which civilization developed and to which life on Earth is adapted, paleoclimate evidence and ongoing climate change suggest that CO2 will need to be reduced from its current 385 ppm to at most 350 ppm. If the present overshoot of this target CO2 is not brief, there is a possibility of seeding irreversible catastrophic effects.

The most difficult task, phase-out over the next 20-25 years of coal use that does not capture
CO2, is herculean, yet feasible when compared with the efforts that went into World War II. The
stakes, for all life on the planet, surpass those of any previous crisis. The greatest danger is
continued ignorance and denial, which could make tragic consequences unavoidable.

Mr. Hansen uses some pretty strong language, but backs it up with some equally strong data. There is also a Powerpoint presentation available here.

In Al Gore’s brand-new slideshow he presents evidence that the pace of climate change may be even worse than scientists were recently predicting, and challenges us to act with a sense of “generational mission” — the kind of feeling that brought forth the civil rights movement — to set it right.

Despite what you may think, Mr. Gore largely get the climate science right. Yes, he over dramatizes some stuff in order to make a point, but for the most part it’s all correct.

Watch the video here.

Seen over at the American Geophysical Union (subscription required). I can’t access it, but here is the abstract:

Current international climate mitigation efforts aim to stabilize levels of greenhouse gases in the atmosphere. However, human-induced climate warming will continue for many centuries, even after atmospheric CO₂ levels are stabilized. In this paper, we assess the CO₂ emissions requirements for global temperature stabilization within the next several centuries, using an Earth system model of intermediate complexity. We show first that a single pulse of carbon released into the atmosphere increases globally averaged surface temperature by an amount that remains approximately constant for several centuries, even in the absence of additional emissions. We then show that to hold climate constant at a given global temperature requires near-zero future carbon emissions. Our results suggest that future anthropogenic emissions would need to be eliminated in order to stabilize global-mean temperatures. As a consequence, any future anthropogenic emissions will commit the climate system to warming that is essentially irreversible on centennial timescales.

I want to read this.