In a few days, James Hansen and several other leading climate scientists will release a major new study, "Target Atmospheric CO2: Where Should Humanity Aim?" in the Open Atmospheric Sciences Journal. You can read a first draft of the study and my commentary on it here: Hansen (et al) ultimatum: Get back to 350 ppm or risk an ice-free planet. Hansen has just put online a draft press release and FAQ (PDF, reprinted below).

First, though, Hansen responds to those of us who were critical of his earlier statement that "neither presidential candidate ‘gets it’, based on their enthusiasm for ‘clean coal’ and ‘carbon cap and trade.’" No Naderite he, says, the NASA scientist: "The vice presidential choices should jolt even the most jaded and somnolent into getting their fannies to the polls, if they retain any concern about life and the planet left for our children."

Back to the draft press release, which warns:

Humanity must find a path to reduced atmospheric carbon dioxide, to less than the amount in the air today, if climate disasters are to be averted, according to a study to be published in Open Atmospheric Science Journal by a group of ten scientists from the United States, the United Kingdom and France. They argue that such a path is feasible, but requires a prompt moratorium on new coal use that does not capture CO2 and phase-out of existing coal emissions by 2030 …

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… if coal emissions were thus phased out between 2010 and 2030, and if emissions from unconventional fossil fuels such as tar shale were minimized, atmospheric CO2 would peak at 400-425 ppm and then slowly decline.

The authors conclude that "humanity today, collectively, must face the uncomfortable fact that industrial civilization itself has become the principal driver of global climate … [T]he 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."

I reiterate that if you agree with Hansen’s analysis of climate science and its implications for concentrations and emissions, then a CO2 price — whether imposed by a tax as Hansen recommends or achieved through a cap-and-trade — is simply beside the point.

It is politically implausible that the nation and the world could adopt a high enough carbon price that gets us off of coal fast enough: Hansen says the rich countries need to be coal-emission-free by 2020 (!), which is long before coal with carbon capture and storage (aka clean coal) will be practical and scalable (see "Is coal with carbon capture and storage a core climate solution?" That means shutting down every coal plant in the industrialized world in a decade. It must simply be labeled "impossible" that even a politically implausible price for carbon would get you the carbon-free electricity and grid infrastructure needed to replace all those coal plants in a decade.

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In short, if you believe Hansen is right, then don’t waste time with a carbon price. We need to go straight to the government-led WWII-style effort for the whole planet that is sustained for decades, as I discuss in the Conclusion to my book (online here, reg. req’d). This is obviously no more politically plausible today than a price for carbon of several hundred dollars. But unlike the carbon price approach, at least the WWII-style approach would work.

Here are more excerpts from the draft PR:

"There is a bright side to this conclusion" according to James Hansen, the lead author on the study, "by following a path that leads to a lower CO2 amount we can alleviate a number of problems that had begun to seem inevitable, such as increased storm intensities, expanded desertification, loss of coral reefs, and loss of mountain glaciers that supply fresh water to hundreds of millions of people."

Atmospheric carbon dioxide is already 385 parts per million (ppm) and it is increasing by about 2 ppm each year as a result of the burning of fossil fuels (coal, oil, and gas), with a smaller contribution from burning of forests. The authors use evidence of how the Earth responded to past changes of CO2 and on-going climate changes to show that atmospheric CO2 has already entered the dangerous zone.

The authors suggest that global policies should have an initial target for atmospheric CO2 of 350 ppm. They note that the optimum CO2 level for maintaining a planet similar to that on which civilization developed is likely to be less than 350 ppm, but a 350 ppm target already reveals that dramatic policy changes are needed urgently. By the time such fundamental changes are achieved, knowledge will exist to help fine-tune the target CO2 …

The authors discredit the notion of ‘geo-engineering’ solutions, noting that with present cost estimates the price of artificially removing 50 ppm of CO2 from the air would be about $20 trillion. They suggest instead that "improved agricultural and forestry practices offer a more natural way to draw down CO2." They suggest that reforestation of degraded land and improved agricultural practices that retain soil carbon could draw down atmospheric CO2 by as much as 50 ppm. Additional significant CO2 reduction could be achieved by using carbon-negative biofuels to replace liquid fossil fuels and phasing out emissions from natural gas-fired power plants, according to the authors. They find that a combination of these approaches could bring CO2 back to 350 ppm well before the end of the century.

The conclusion that humanity must aim for a CO2 amount less than the current amount is a dramatic change from most previous studies, which suggested that the dangerous level of CO2 was likely to be 450 ppm or higher. The change is caused by realization that ‘slow’ feedback processes, such as ice melt and release of greenhouse gases by the soil and ocean in a warming climate, can occur on the time scale of decades and centuries. This realization stems from both improving data on the Earth’s climate history and ongoing observations of change, especially in the polar regions.

Strong stuff. I will post a link to the study and the PR when they are final.

I would also recommend reading the draft FAQ, which covers topics such as:

  • Less than 350 ppm
  • China and India
  • Coal and R&D program for nuclear power
  • Greenwash
  • Inter-generational inequity and injustice
  • Protests against government inactions