Climate Progress: An insider's view of climate science, politics, and solutions

The nation’s top climate scientists, James Hansen, has just published a general-audience article, “Tipping Point,” in “2008-2009 State of the Wild,” from Island Press. It is well worth sending to folks who don’t like all the math. His key points:

We are at the tipping point because the climate state includes large, ready positive feedbacks provided by the Arctic sea ice, the West Antarctic ice sheet, and much of Greenland’s ice….

Prior major warmings in Earth’s history, the most recent occurring 55 million years ago . . . resulted in the extinction of half or more of the species then on the planet….

In my view, special interests have undue sway with our governments and have effectively promoted minimalist actions and growth in fossil fuels, rather than making the scale of investments necessary.

You might also like this figure on “cumulative fossil fuel carbon dioxide emissions by different countries as a percent of global total”:

China has a long way to go to catch up to this country — let alone the entire industrialized world — on cumulative emissions (though they are obviously trying as hard as they can).

The good news: The earth’s carbon cycle has natural negative feedbacks that reverse natural surges in carbon dioxide.

The bad news: We are spewing CO2 into the atmosphere 14,000 times faster than nature has over the past 600,000 years, far too quickly for those feedbacks to respond.

This comes from “Close mass balance of long-term carbon fluxes from ice-core CO2 and ocean chemistry records,” in Nature Geosciences (subs. reqd, news article here) by Zeebe and Caldeira. Put another way:

“These feedbacks operate so slowly that they will not help us in terms of climate change … that we’re going to see in the next several hundred years,” Zeebe said by telephone from the University of Hawaii. “Right now we have put the system entirely out of equilibrium.“

Zeebe notes that, “the average change in the amount of atmospheric carbon dioxide over the last 600,000 years has been just 22 parts per million by volume.” Humans have run up CO2 levels 100 ppm over the last two centuries!

In the ancient past, excess carbon dioxide came mostly from volcanoes, which spewed very little of the chemical compared to what humans activities do now, but it still had to be addressed.

This antique excess carbon dioxide — a powerful greenhouse gas — was removed from the atmosphere through the weathering of mountains, which take in the chemical….

The natural mechanism will eventually absorb the excess carbon dioxide, Zeebe said, but not for hundreds of thousands of years.

See, the skeptics were right: The planet is self-healing. You go, deniers [no, seriously, please, just go]! So my great-great-great-great — [insert 10,000 "greats" here] — great-great-great grand-kid will be doing just fine, thank you very much!

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[I am retroactively inserting this entry in the series for the sake of completeness. Much of the content has been previously posted.]

What happens if we fail to take the following actions to reverse emissions trends starting in 2009?

1. Start a cap-and-trade system that sets a serious price for CO2.
2. Launch most of the 14 to 16 major mitigation strategies (wedges) described here.
3. Begin a global effort to ban new coal plants that do not capture and store their carbon, an effort that quickly brings in China and other developing countries.

Failing to do that, we are headed to 800 to 1000 parts per million (ppm) of atmospheric carbon dioxide.

The idea of stabilizing at, say, 550 or 650 ppm, widely held a decade ago, is becoming increasingly implausible given the likelihood that major carbon cycle feedbacks would go into overdrive, swiftly taking the planet to 800 ppm or more. In particular, the top 11 feet of the tundra would probably not survive 550 ppm (a point I will be blogging about soon) and two other key carbon sinks — land-based vegetation and the oceans — already appear to be saturating. That said, even if stabilizing at 550 ppm were possible, it would probably bring catastrophic impacts and in any case requires implementing some 10 wedges starting now.

At 800 to 1000 ppm, the world faces multiple miseries, including:

1. Sea level rise of 80 feet to 250 feet at a rate of 6 inches a decade (or more).
2. Desertification of one third the planet and drought over half the planet, plus the loss of all inland glaciers.
3. More than 70% of all species going extinct, plus extreme ocean acidification.

LIVING/SUFFERING IN A 1000 PPM WORLD

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“He that troubleth his own house shall inherit the wind.” A Biblical proverb for our times, it turns out….

The bark beetle is devastating North American trees (see “Climate-Driven Pest Devours N. American Forests“).

Global warming has created a perfect climate for these beetles — Milder winters since 1994 have reduced the winter death rate of beetle larvae in Wyoming from 80% per year to under 10%, and hotter, drier summers have made trees weaker, less able to fight off beetles. [Picture shows forests turned red by beetle.]

New reseach published in the journal Nature, “Mountain pine beetle and forest carbon feedback to climate change,” (subs. req’d, abstract reprinted below), quantifies the current and future impact just from the beetle’s warming-driven devastation in British Columbia:

… the cumulative impact of the beetle outbreak in the affected region during 2000–2020 will be 270 megatonnes (Mt) carbon (or 36 g carbon m^-2 yr^-1 on average over 374,000 km² of forest). This impact converted the forest from a small net carbon sink to a large net carbon source.

No wonder the carbon sinks are saturating faster than we thought (see here) — unmodeled impacts of climate change are destroying them:

Insect outbreaks such as this represent an important mechanism by which climate change may undermine the ability of northern forests to take up and store atmospheric carbon, and such impacts should be accounted for in large-scale modelling analyses.

Any “good news” here? Only if you like very dark irony. The accompanying news story (here, subs. req’d) notes:

Even if climate change brings further warm winters to the region, however, experts think this infestation has probably peaked. Mountain pine beetles can only reproduce in the largest trees, which were abundant thanks to a growth spurt after wildfires raged across western North America 80 to 140 years ago. Soon 80 to 90% of those large trees will be gone, Kurz says. “The beetle will eat itself out of house and home, and the population will eventually collapse.”

Hmm. “Eat itself out of house and home.“ Does the bark beetle sound like any other species we know? Finally, the species formerly known as homo sapiens sapiens is no longer alone in its self-destructive quest to destroy its habitat. Inhert the wind, indeed.

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