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Reading University

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Mea Culpa

2 February 2014

Mea Culpa

By Gwynne Dyer

Confession is good for the soul, and my soul is certainly in need of improvement, so here is a confession. I got it wrong in my article “Geo-Engineering in Trouble”, sent out on 15 January. I couldn’t be happier about that.

The article said that a new scientific study, carried out by Angus Ferraro, Ellie Highwood and Andrew Charlton-Perez of Reading University, showed that the most widely discussed geo-engineering method for holding the global temperature down would have disastrous consequences for agriculture. The method is injecting sulphur dioxide into the stratosphere; the (unintended) result would be devastating drought in the tropics.

The idea of using sulphate aerosols in the stratosphere to reflect back some incoming sunlight, thus lowering surface temperatures on Earth, has been the leading contender for a geo-engineering solution to runaway heating since the whole subject came out of the closet eight years ago. And then along come “Ferraro et al.” (as the scientists put it) to tell us that the side-effects will be disastrous. Thanks, guys.

So I ended the article by saying: “The sulphur dioxide technique was the cheapest and seemingly the best understood option for holding the temperature down. A great many people were glad that it was there, as a kind of safety net if we really don’t get our act together in time to halt the warming by less intrusive means. Now there’s no safety net.”

Almost immediately I got an email from Andy Parker, now a research fellow in the Kennedy School at Harvard University and previously a climate change policy advisor for the Royal Society in the United Kingdom. You’ve been suckered by the publicity flacks at Reading University, he said (though in kinder words). They have spun the research findings for maximum shock value. In other words, read the damn thing before you write about it.

Well, actually, I did read it (it’s available on-line), but the conclusions are couched in the usual science-speak, with a resolute avoidance of anything that might look like interpretation for the general public. I didn’t look long enough at the key graph that undercuts the dire conclusions of the publicists, presumably because I had already been conditioned by them to see something else there.

Drastic consequences would indeed ensue if you tried to geo-engineer a 4 degrees C warmer world all the way back down to the pre-industrial average global temperature by putting sulphate aerosols in the stratosphere. But nobody in their right mind would try to do that.

On the other hand, if you were using sulphates to hold the temperature down to plus 1.8 degrees C, in a world where the carbon dioxide content of the atmosphere would otherwise give you plus 4 degrees C, then the effect on tropical rainfall would be small. And that is a far likelier scenario, because we are most unlikely to resort to large-scale geo-engineering until we are right at the threshold (around plus 2 degrees C) of runaway warming.

So the correct conclusion to draw from Ferrero et al. is that geo-engineering with sulphates is still one of the more promising techniques for holding the temperature down, and should be investigated further. As Andy Parker put it, “this does not tell us that we should do geo-engineering, but it does mean that the paper is a long way from being the nail in the coffin that the press release implies.”

And then I got another email, this time from my old friend Amory Lovins, co-founder and chief scientist at the Rocky Mountain Institute, who took me to task for assuming that human greenhouse gas emissions “probably will not drop” fast enough to prevent us from going into runaway warning (unless we geo-engineer) later this century.

Not true, he said. “Since the Kyoto conference in 1997, most efforts to hedge climate risks have made four main errors: assuming solutions will be costly rather than (at least mainly) profitable; insisting they be motivated by concerns about climate rather than about security, profit, or economic development; assuming they require a global treaty; and assuming businesses can do little or nothing before carbon is priced.”

“As these errors are gradually realized, climate protection is changing course. It will be led more by countries and companies than by international treaties and organizations, more by the private sector and civil society than by governments, more by leading developing economies than by mature developed ones, and more by efficiency and clean energy’s economic fundamentals than by possible future carbon pricing.”

He pointed out how strongly China is committed to clean energy. Last year renewables, (including hydro) accounted for 43 percent of new generating capacity in China, as the extra coal plants ordered long ago taper sharply down. India is showing signs of moving in the same direction, and there’s even hope that Japan may decide to replace all the nuclear capacity it is shutting down with renewables rather than coal.

So I shouldn’t be so pessimistic, they were both telling me. I believe Andy Parker is right, and I hope Amory Lovins is right too. But just in case Amory is a bit off in the timing of all these turn-arounds on greenhouse gas emissions in Asia, I would still like to see a lot of research, including small-scale experiments in the open atmosphere, on the various techniques for geo-engineering.

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To shorten to 725 words, omit paragraphs 3, 11 and 12. (“The idea…guys”; and “Not…pricing”)

Gwynne Dyer is an independent journalist whose articles are published in 45 countries.

 

Geo-Engineering in Trouble

15 January 2014

Geo-Engineering in Trouble

By Gwynne Dyer

Bad news on the climate front. It was already clear that we are very likely to break through all the “do not exceed” limits and go into runaway warming later this century, because greenhouse emissions have not dropped, are not dropping, and probably will not drop. We did have a fall-back position, which was to counter the warming by geo-engineering – but now the leading technique for geo-engineering also looks like it will not work.

In a paper published this month in “Environmental Research Letters”, three researchers at Reading University in England have shown that trying to cool the planet by putting large amounts of sulphur dioxide into the stratosphere would lead to a 30 percent decline in rainfall in most of the tropics. That would mean permanent drought conditions in countries like Indonesia, and millions would starve.

Starvation is the main impact that higher average global temperatures will have on human beings, as they will cause a big loss in food production, particularly in the tropics and sub-tropics. But the standard assumption was that there would still be as much rain in the tropics as before. Maybe even too much rain, as the heat would mean higher rates of evaporation and more powerful tropical storms.

What Drs. Angus Ferraro, Ellie Highwood and Andrew Charlton-Perez have done is to use several climate model simulations to examine the effect of geo-engineering on the tropical overturning circulation. This circulation is largely responsible for lifting water vapour that has evaporated at the surface high enough up into the atmosphere that it turns back into water droplets and falls as rain. If the circulation gets weaker, so does the rainfall.

Putting sulphur dioxide into the stratosphere to cut the amount of incoming sunlight and reduce heating at the surface was first suggested by Paul Crutzen, a Nobel Prize-winning atmospheric chemist, in 2006. At that time, talking about geo-engineering was taboo among scientists, because they feared that if the general public knew that the heating could be held down that way, they’d stop trying to curb their greenhouse gas emissions.

Crutzen violated the taboo because countries and people were NOT cutting their emissions, and there was no reasonable prospect that they would. (This is still largely the case, by the way.) So the world definitely needed a Plan B if we did not want to see a planet that is 4 degrees C hotter (7 degrees F) by the end of the century.

Crutzen pointed out that large volcanoes, when they explode, put substantial amounts of sulphur dioxide gas into the stratosphere. That causes significant cooling at the surface for one or two years, until it all comes down again – and it does no apparent harm in the process. The last big volcano to explode, Mount Pinatubo in the Philippines in 1991, reduced the average global temperature at peak by half a degree C (one degree F).

Human beings could also put sulphur dioxide into the stratosphere (on a rather larger scale), to hold the temperature down, said Crutzen. The ice caps wouldn’t melt, our agriculture would continue to get the familiar weather it needs, and we would win ourselves more time to get our emissions down. We still have to get our emissions down in the end, he stressed, but it would be better not to have a global calamity on the way from here to there.

There was so much outrage at Crutzen’s suggestion that he had a nervous breakdown, but then lots of other scientists came out of hiding to admit that they also thought the human race needed a fall-back position. Various other proposals for holding the temperature down were put on the table, and by now there are dozens of them, but the idea of putting sulphur dioxide in the stratosphere still led the field. Until now.

But the Reading University scientists have discovered a hitherto unsuspected side-effect of this kind of geo-engineering. The sulphur dioxide particles don’t just reflect back a portion of the incoming sunlight from above. They also reflect a portion of the long-wave radiation (heat) coming back up from the surface, and that heats the top of the troposphere.

The troposphere is the lower part of the atmosphere, where all the weather happens. If you heat the top of the troposphere, you reduce the temperature difference between there and the surface, so the tropical overturning circulation weakens. That means less water vapour is carried up, and less rain falls back down. Result: drought and famine.

This is exactly the kind of scientific investigation that Crutzen wanted. He understood clearly that we were venturing into dangerous territory when we start intervening in a system as complex as the climate, and he stressed that what was needed was lots more research before we have to gamble on geo-engineering to halt an imminent disaster. But it’s a very discouraging conclusion.

The sulphur dioxide option was the cheapest and seemingly the best understood option for holding the temperature down. A great many people were glad that it was there, as a kind of safety net if we really don’t get our act together in time to halt the warming by less intrusive means. Now there’s no safety net.

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To shorten to 725 words, omit paragraphs 9 and 12. (“There…now”; and “This…conclusion”)

Gwynne Dyer is an independent journalist whose articles are published in 45 countries.