It’s not too late to avert the worst impacts of human-caused global warming. In fact, it’s not too late to stabilize total warming from preindustrial levels at 1.5°C — or possibly less. But the U.S. must pass a comprehensive climate and clean energy bill, leading to a major global deal, to give us a plausible chance of getting on the necessary emissions pathway.
From a scientific perspective, a major new study (subs. req’d, discussed below) is cause for some genuine non-pessimism, concluding “Near-zero CH4 growth in the Arctic during 2008 suggests we have not yet activated strong climate feedbacks from permafrost and CH4 hydrates.”
The media and others want to move quickly from denial to despair, because both perspectives justify inaction, justify maintaining our grotesquely unsustainable behavior, justify sticking with the global Ponzi scheme in the immoral delusion we can maintain our own personal wealth and well-being for a few more decades before the day of reckoning.
I have, however, received a number of queries from progressives about the meaning of this somewhat misleading Washington Post article, “New Analysis Brings Dire Forecast Of 6.3-Degree Temperature Increase,” which begins:
Climate researchers now predict the planet will warm by 6.3 degrees Fahrenheit by the end of the century even if the world’s leaders fulfill their most ambitious climate pledges, a much faster and broader scale of change than forecast just two years ago, according to a report released Thursday by the United Nations Environment Program….
Robert Corell, who chairs the Climate Action Initiative and reviewed the UNEP report’s scientific findings, said the significant global temperature rise is likely to occur even if industrialized and developed countries enact every climate policy they have proposed at this point. The increase is nearly double what scientists and world policymakers have identified as the upper limit of warming the world can afford in order to avert catastrophic climate change.
I don’t think the basic story should be a surprise to regular readers of this blog. We’re in big, big trouble, and we’re not yet politically prepared to do what is necessary to avert catastrophe — as I’ve said many times. But that is quite different from concluding it’s too late and we’re doomed.
The WashPost story is about the Climate Rapid Overview and Decision-support Simulator — the C-ROADS model. It “translates complex climate modeling into readily digestible predictions” and “is being adopted by negotiators to assess their national greenhouse-gas commitments ahead of December’s climate summit in Copenhagen,” as explained in a recent Nature article (subs. req’d, excerpted here).
As one of the leading C-ROADS modelers — my friend Drew Jones — explained in his blog, the Post headline could have easily been:
“New Analysis Shows Growing Commitment to a Global Deal Will Help Stabilize Climate.”
The first thing to remember is that the major developed countries, including China or India, haven’t agreed to cap their emissions, let alone to ultimately reduce them. Until that happens, no model of global commitments is going to keep us anywhere near 2°C (3.6F).
Second, people forget that the 1987 Montr©al protocol would not have stopped the atmospheric concentration of ozone-destroying chemicals from rising forever. And yet we appear to have acted in time to save the ozone layer.
Third, people also seem to forget that the United States government led by President Bush’s father, and including the entire Senate, agreed that we would tackle global warming the same way — with the rich countries going first.
I have no doubt that China will ultimately agree to a cap (see “Peaking Duck: Beijing’s Growing Appetite for Climate Action”). Indeed, if a shrinking economy-wide cap on GHGs similar to the House bill or draft Senate bill ends up on Obama’s desk in the next few months, then the international community will almost certainly agree on a global deal, which will include China sharply reducing its business-as-usual growth path. Then in the next deal in a few years, China will, I expect, agree to a cap no later than 2025.
But I’m getting ahead of myself. This is an important issue that I will treat in a multipart series. People seem to view this question of “Is it too late?” as if it were primarily a scientific issue, but that is because they have internalized their preconceptions about what is politically possible in terms of clean energy deployment in this country and around the world.
There is no evidence scientifically that it is too late to stabilize at 350 ppm atmospheric concentrations of carbon dioxide, at 1.5°C total planetary warming from preindustrial levels. Nor is there any scientific evidence that we can’t afford to overshoot 350 ppm — as we already have — for a period of many decades.
True, I don’t view it as likely that we will stabilize at 1.5°C warming. But that overlays my view of the science with my view of the solutions and the politics. I do think it is entirely possible that we will stabilize under 450 ppm, near 2°C. That’s a key reason why I blog. It would, however, probably require a heroic WWII-style and WWII-scale effort by the nation and the world starting sometime in the next decade.
This post will briefly touch on the science. Future posts will consider climate solutions and the needed domestic and international action to employ them at the necessary scale and speed.
The catastrophe we are trying to avert is multimeter sea level rise, the loss of the inland glaciers that provide water to a billion people, rapid expansion of the subtropical deserts (i.e. Dust-Bowlification of one third the habited land mass), killing off more than half of all species and turning the oceans into hot, acidic dead zones “” each of which is all-but inevitable on our current path of unrestrained greenhouse gas emissions (see “An introduction to global warming impacts: Hell and High Water”).
No one knows for certain what level of emissions is needed to avert that series of catastrophes. Indeed, some of these catastrophes occur at much lower levels of emissions than others. And some may play out over very long periods of time, but still become all but unstoppable at much lower levels of emissions.
The literature makes clear that as you go above 450 ppm and 2°C, these impacts become more likely, more intense, and more imminent. In fact, no one knows for certain whether one can, in fact, stabilize at, say 550 ppm and roughly 3°C warming — in any meaningful definition of the word “stabilize” (which does not include desperately devoting all of humanity’s resources to sucking every last drop of CO2 and CH4 from the energy system and atmosphere).
Whatever the threshold is, staying above it for any length of time risks a rapid acceleration of emissions that will make it all but impossible to get back below that point of no return. Hansen and his leading scientific coauthors have made a case we must ultimately return atmospheric concentrations of carbon dioxide to 350 parts per million to avoid catastrophic climate impacts (see “Stabilize at 350 ppm or risk ice-free planet, warn NASA, Yale, Sheffield, Versailles, Boston et al”). But they don’t know — and on one knows — how long we can safely stay above 350.
If I have read Hansen et al. correctly, then I think they may be mostly right for a different reason than he thinks, which is to say, I think the carbon-cycle feedbacks act as the equivalent of the amplifiers that he models: “Additional warming, due to slow climate feedbacks including loss of ice and spread of flora over the vast high-latitude land area in the Northern Hemisphere, approximately doubles equilibrium climate sensitivity.”
It is increasingly clear that the virtually all of the major carbon cycle feedbacks are positive — see Science stunner: “Clouds Appear to Be Big, Bad Player in Global Warming” “” an amplifying feedback (sorry Lindzen and fellow deniers) and Study: Water-vapor feedback is “strong and positive,” so we face “warming of several degrees Celsius”). These include
- The defrosting of the permafrost
- The drying of the Northern peatlands (bogs, moors, and mires).
- The destruction of the tropical wetlands
- Decelerating growth in tropical forest trees “” thanks to accelerating carbon dioxide
- Wildfires and Climate-Driven forest destruction by pests
- The desertification-global warming feedback
- The saturation of the ocean carbon sink
In short, if you get near 450 ppm and stay there for any length of time, you will shoot up to 800 to 1000 ppm, which certainly gets you an ice-free planet and other unimaginably catastrophic impacts.
But we aren’t there yet, and we can stay below 450 and get back to 350 (or lower) this century if we choose to.
The best piece of scientific news I have read in a while comes from a NOAA-led study, “Observational constraints on recent increases in the atmospheric CH4 burden” (subs. req’d, NOAA online news story here), which found:
Measurements of atmospheric CH4 from air samples collected weekly at 46 remote surface sites show that, after a decade of near-zero growth, globally averaged atmospheric methane increased during 2007 and 2008. During 2007, CH4 increased by 8.3 ± 0.6 ppb. CH4 mole fractions averaged over polar northern latitudes and the Southern Hemisphere increased more than other zonally averaged regions. In 2008, globally averaged CH4 increased by 4.4 ± 0.6 ppb; the largest increase was in the tropics, while polar northern latitudes did not increase. Satellite and in situ CO observations suggest only a minor contribution to increased CH4 from biomass burning. The most likely drivers of the CH4 anomalies observed during 2007 and 2008 are anomalously high temperatures in the Arctic and greater than average precipitation in the tropics. Near-zero CH4 growth in the Arctic during 2008 suggests we have not yet activated strong climate feedbacks from permafrost and CH4 hydrates.
Yes, early this year I reported that NOAA found “Methane levels rose in 2008 for the second consecutive year after a 10-year lull,” but so far that most dangerous of all feedbacks — Arctic and tundra methane releases — does not appear to have been fatally triggered.
Now it should be said that even if it did start, it doesn’t mean we couldn’t drop total emissions faster than the feedbacks overwhelmed them — it just means it would be much, much, much harder to do so.
Those who suggest it is too late are combining a scientific judgment that I believe is not yet possible to make with judgments about climate solutions and our political will to employ them fast enough that may prove true, but which are subjective judgments nonetheless — and that’s quite different from saying “it’s too late.”
In Part 2, I’ll look at the scale of the energy challenge, which simultaneously makes clear how difficult the political challenge is and how very far we can go using existing and near-term strategies (including behavior change, which is at one level much harder, and at another level, potentially the fastest change of all).