The Dawn of the Age of Climate Engineering
New Haven: Yale University Press, March 2013
Now that the reality of climate change and the problems it poses are becoming widely recognized, attention is turning increasingly to methods of preventing or lessening those problems. The general term for all these methods is "geoengineering" because they involve engineering applied to the entire globe.
Within that blanket term, geoengineering methods fall into two groups: methods that remove carbon dioxide from the atmosphere, and methods that control the amount of sunlight absorbed by the planet.
The least expensive ways of removing carbon dioxide from the atmosphere for long periods (CO2 sequestration) are biological. They involve using micronutrients to foster the rapid growth of organisms which consume carbon dioxide. It quickly becomes apparent, however, that these biological methods of sequestration are fraught with risk.
For example, adding relatively small amounts of iron to ocean waters fosters the growth of algae. This is perhaps the most popular method of biological sequestration. However, unless the iron joins other nutrients like silicon, the algae that capture the CO2 are eaten by copepods and the carbon dioxide soon returns to the atmosphere. Silicon fosters the growth of diatoms, whose hard shells carry carbon down to the "abyssal zone" (the depths of the ocean), where it remains for eons.
As shown by the LohaFex experiment in 2009, the downside of this iron fertilization is the large area of ocean that must be seeded to sequester useful quantities of CO2.
"The researchers estimate that if the silicon-rich third of the Southern Ocean were seeded with iron, the biological pump would at most take 1 billion tonnes of carbon dioxide from the atmosphere each year. On that basis, the deployment of full-scale iron fertilization would see a third of the Southern Ocean — around 5 per cent of the Earth's surface — serve as a sink for a tenth of the world's current annual excess carbon dioxide emissions."
– Page 35
When the author turns to consideration of way to adjust the amount of sunlight warming the planet (SRM, or solar radiation management), he finds just as much reason to fear unanticipated consequences. In this area, pumping sulfur into the stratosphere to form long-lived reflective aerosols is the low-cost option. But it too carries the risk of side effects: eroding the ozone layer, changing weather patterns.
These unintended results are why many scientists look askance at geoengineering. Yet momentum to use it is building, because it is potentially lucrative and offers a Plan B if Plan A — large reductions in CO2 emissions — are never enacted (a failure that looks increasingly likely.)
In chapters 2 and 3, the author presents some conclusions I think unjustified. In particular, his treatment of biological and chemical methods to pull carbon dioxide out of the air seems cursory and intended to discredit the entire concept. However, it is true that the question of where to store all that captured greenhouse gas has no good answer so far. And some of his explanations fall short. Consider this one:
"It is well known that as the sea-ice in the Arctic melts the Earth loses some of its albedo or reflectivity — white ice is replaced by dark seawater which absorbs more heat. If a large area of the Earth's surface could be whitened then more of the Sun's warmth would be reflected back into space rather than absorbed. A number of schemes have been proposed, including painting roofs white, which is unlikely to make any significant difference globally.1 What might be helpful is to cut down all of the forests in Siberia and Canada. While it is generally believed that more forests are a good thing because trees absorb carbon, boreal (northern) forests have a downside. Compared to the snow-covered forest floor beneath, the trees are dark and absorb more solar radiation. If they were felled the exposed ground would reflect a significantly greater portion of incoming solar radiation and the Earth would therefore be cooler. If such a suggestion appears outrageous it is in part because matters are never so simple in the Earth system. Warming would cause the snow on the denuded lands to melt, and the situation would be worse than before the forests were cleared."
– Page 2
From this description, I cannot tell for sure whether cutting those forests will warm or cool. Any discussion of the technical merits of a procedure should be clearer and more detailed. But the remainder of the book is excellent. Chapter 4, "The Players and the Public," is especially good. On page 94, Hamilton calls out The Australian, Rubert Murdoch's flagship newspaper, for its ongoing denigration of climate science.
"These campaigns are bewildering until we remember that resisting environmental regulations, including energy efficiency measures, has become a sign of red-blooded faith in the prevailing system, the particular conservative construction of the American way of life. The ideological framing of environmentally benign technology has a long history in the United States. When Sherwood Rowland, the American chemist who would share the 1995 Nobel Prize with Paul Crutzen, advocated a ban on ozone-destroying consumer products, the aerosol spray-can industry suggested he was a KGB agent bent on destroying capitalism."
– Page 94
This is the great danger: that effective action to mitigate climate change will be blocked by advocates of the false justification that some sweeping technical solution is just around the corner. In fact, we have all the technology we need to solve the problem; what we lack is the will to deploy it. We can begin to replace aging fossil-fuel power plants with renewables. (Indeed, we could have begun twenty years ago.) At the same time, those who dismiss energy conservation and alternative sources like wind and solar demonstrate unbounded faith in unproven technologies like "clean coal."
Hamilton understands this danger very well. Yet he can still write:
"One response to the arrival of the Anthropocene, the usual one, is to argue that it has arisen because of a regrettable failure of foresight. We have not given enough thought to the side effects of our technological progress, so to save the situation we need better scientific understanding and technological know-how. On this view, the response to the climate crisis and the broader dangers presented by the Anthropocene lies in raising to a higher level the characteristic of humans that makes us distinct as a species, our reasoning capacity. The disruption of the Anthropocene demands that we redouble our belief in the perfectibility of humankind. Yet how can we think our way out of the problem when the problem is the way we think?"
– Page 199
Here, he forgets that energy conservation is not only changes in behavior such as driving less; it is measures like using Energy Star refrigerators and insulating attics in private homes. Those too are technological know-how. And if changing the way we think is to be dismissed, that seems to preclude any alteration in the pervasive mantra that unbridled growth is always good. I get the impression that Hamilton here falls into a trap himself. It is the common one of regarding any technical solution as suspect merely because it is technical rather than behavioral.
Hamilton, Professor of Public Ethics at Charles Stuart University in Canberra, has written an excellent treatment of the moral dilemmas attendant to global warming. Each chapter is extensively end-noted, and those references form a rich source of links to on-line resources. The index is good, and my spot checks found no errors in it. Errors of grammar are few. I recommend this valuable book and consider it a keeper. However, I have to knock its rating down one notch because of its cursory treatment of technical issues.