Counting the ways we could be screwed by abrupt climate swings. Avoiding them? It's not all about CO2

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We interrupt Dateline Earth's relentless search for the 100 one-percent solutions to global warming for a special report on a sweeping new look at how we can give ourselves a lot more time to find those solutions.

rm iwest mugA collection of papers just published in the Proceedings of the National Academy of Sciences highlights a series of steps that would forestall the worst effects of climate change by years or even decades. That gives us a lot more time to develop the technology it's going to take to get us out of this mess. (Although, as we've pointed out before, we already have the know-how to cut emissions 80 percent by 2020.)

The research is aimed at avoiding the "tipping points" that scientists fear could make the fight unwinnable -- abrupt, irreversible climate change. You know, stuff like permafrost melting, changes in the African winds that bring nutrients to the Amazon and methane bubbling up from the ocean bottom in world-changing quantities. (See the summary.)

Most of this series of scientific papers is devoted to this laundry list of Things That Could Go Really Wrong Really Fast. But there's hope! Read on. 

Now, the funny thing about this collections of papers is the proposed solutions, the ones to forfend sudden and dramatic climate change, do not target the most prolific greenhouse gas, carbon dioxide. That's the gas the global climate negotiators are focused on in Copenhagen this week.

No, the final paper in the bunch says the two most surefire ways to head off what they call "tipping elements" is to stop using hydrofluorocarbons, or HFCS, and stop polluting the air so much. 

You see, carbon dioxide is not as potent as other greenhouse gases, even though it's the most abundant. And it hangs around in the atmosphere for hundreds of years compared to, say, methane, which is up there maybe a dozen years before it turns into CO2. Methane, though, is a much more potent greenhouse gas than CO2. So, ounce for ounce, the more you keep out of the air, the better off we'll be, and especially in the short term.

Same for hydroflurocarbons, the  manmade chemicals that are being phased out in an effort to protect the ozone layer.

The very same thing goes for black carbon -- soot, essentially, from diesel exhausts, burning wood and so forth.

And you can say the same thing about ground-level ozone. (Which is caused by air pollution, doesn't protect us from anything and even harms us, unlike the ozone layer way up in the atmosphere that screens out the sun's most-harmful rays.)

The whole idea in avoiding these massive and no-doubt-harmful climate shifts is to keep the increase in temperatures, expressed as a global average, to no more than 2 degrees Centigrade.

Commenting on the solutions suggested in his paper is Mario Molina, a scientist who won a Nobel Peace Prize for laying out the threat to the ozone layer in the 1970s. That led to the Montreal Protocol, the global treaty to phase out hydrofluorocarbons and other chemicals harmful to the ozone layer:

 The Montreal Protocol has already delayed climate change by seven to 12 years, and put the ozone layer on the path to recovery later this century. The Montreal Protocol is critical for avoiding abrupt climate change.  We have to take advantage of the proven ability of this legally binding treaty to quickly phase down HFCs.

As for black carbon soot, here's something to consider: Although burning biomass has been touted as a solution to global warming, it produces the black carbon, which is now considered a leading cause of global warming. For instance, when the carbon lands on snow, in large quantities, it helps melt the snow, because the black particle absorb a lot more heat than the white snow. All of which makes things warmer.

Summarizing the hopeful part of the research is co-author Veerabhadran Ramanathan of the University of California at San Diego:

Cutting HFCs, black carbon, tropospheric ozone, and methane can buy us about 40 years before we approach the dangerous threshold of 2˚C warming. ... If we reduce black carbon emissions worldwide by 50 percent by fully deploying all available emissions-control technologies, we could delay the warming effects of CO2 by one to two decades and at the same time greatly improve the health of those living in heavily polluted regions.

Now, these are scientists, and they've been watching the world stage on climate for some time now. In a roundup paper, German researcher Hans Joachim Schellnhuber sounds positively bleak:

Whether this precautionary approach is an option at all, after two decades of failed climate protection since the 1999 Intergovernmental Panel of Climate Change Report, is more doubtful than ever.

He sounds a bit more sanguine in a press release, but that's just about this new reasearch:

 This is the first systematic analysis of the tipping elements issue. We have developed a mathematical formalism for describing tipping elements and we have reviewed the complete pertinent literature. We have also identified the tipping elements in the Earth’s climate systems with regard to their relevance for climate policy. One could look at this paper as a “mini-IPCC-report” focusing on tipping elements.

Will this miniature version of the worldwide climate report spur any more change than those that came before?

-- Robert McClure




























































I've been following the discussions about black carbon and short-lived species for a little while. One of the key differences that I see between the short-lived species (especially black carbon) and CO2 is that reducing the short-lived species can provide concrete benefits in the short term, whereas the benefits of CO2 reduction tend to be too abstract and long term. Cleaning up diesel engines in the U.S., for example, would lead to cleaner air and better respiratory health in the near term, often with results that we can see (like tailpipes that formerly spewed clouds of smoke now spewing nothing). In the developing world, more efficient cook-stoves make for less smoke in the cooking area, healthier mothers and children, and less effort to collect or buy fuel. It's something people instinctively understand. And so it's possible that spending foreign aid dollars on cookstoves could attract more political support in the U.S. than something like forest preservation or some kind of mystical regime of credits and trading. A series of reports at the Lancet followed this line of reasoning in great detail, describing how "Cutting greenhouse pollutants could directly save millions of lives worldwide: Analyses show global health benefits from cutting ozone and black carbon" (
Nice, Robert! But even if implemented, haven't we functionally passed at least a few tipping points? Do you think we still CAN back our way out of this, within, say, the lifetime of anyone we might ever know?