Superbunkonomics: cooling the Earth with sulphur dioxide
Editor’s note: Stepping back from the gulf coast to a world-wide perspective, in my opinion the paramount coastal problem is the increasingly obvious manifestation of anthropogenic climate change (ACC) as more and more members of the still growing 6.8 billion population adopt the energy-intensive, carbon dioxide-belching American lifestyle. This science-based conviction is ironic, in that new scientific evidence implies that an ancient period of rapid climate change in the seat of humanity in Africa may have provided a major impetus for the evolution of human intelligence.
I write this having just watched Becoming Human, the first in a Nova three part science series on human evolution produced by the Public Broadcasting System (PBS). A major theme of this show was that we now know that the brain size of prehumans in the Great Rift Valley of Africa increased rapidly from 2.5 to 0.5 million years ago, coinciding with a period of rapidly fluctuating wet and dry periods in the region.
This new information has spawned a theory that pre-human brain size expanded as a response to rapid climate change. It is thought that only the smartest of our ancestors were able to adapt to and survive the rigors caused by these fluctuations.
I hasten to point out that the ancient climate change in at least a part of the African continent was not anthropogenic – a half million years ago our ancestors numbered in the thousands, not billions and when they learned how to tame fire they burned wood, not coal.
Rather than grousing about climate change deniers, this post focuses on climate change “authorities” who increase public confusion by popularizing misinformation. Case in point, I call your attention to a new book with the sexy title Superfreakonomics. The complete title shown on the book jacket (above), highlights the climate change theme. This book was written by Steven Levitt, an economics professor at the University of Chicago and a journalist named Stephen Dubner.
Levitt was interviewed recently on National Public Radio (NPR), and the network carried a book review of Superfreakonomics on November 2. I heard the interview and remember Levitt downplaying orthodox responses to climate change, including photovoltaics, wind power and conservation. Neither the interviewer nor the book review challenged Levitt’s controversial points of view.
For example, Levitt promoted a radical approach to reducing global temperature called aerosol geoengineering, injecting sulfur dioxide into the stratosphere to simulate the shading effect of a massive volcanic eruption. This is the idea of “global cooling,*” which appeals to engineers looking for cookbook solutions and those who are clueless about the complexity of climate and the biosphere,** let alone global politics.
Another irony: atmospheric sulphur dioxide (SO2), which causes acid precipitation, prompted a successful cap-and-trade pollution marketing system in the early 90s that is the model for the CO2 cap-and-trade system currently under debate in Congress.
In contrast to Levitt’s book for lay consumption, Real Climate is a highly credible web-based technical journal by and for serious climate interests, which recently published a detailed critique of Superfreakonomics. The critique was written by a credentialed specialist on climate change, Raymond T. Pierrehumbert, Professor of Geophysics, also on the faculty of the University of Chicago.
For anyone who possibly carries the “geek gene” I strongly recommend carefully reading the Professor’s scathing dismissal of Levitt’s pontifications on climate change.
Unlike Professor Pierrehumbert, I don’t have the geophysics background to check Levitt’s calculations on the feasibility of photovoltaic electricity. On the other hand I do have enough common sense to challenge this economist’s glib endorsement of “global cooling.”
The climate expert’s critique specifically refutes two fundamental fallacies in the book: (1) that to be significant, photovoltaic power generation would require a huge portion of the total land surface on Earth, displacing other uses and creating net warming by decreasing albedo; and (2) that global cooling is realistic and feasible.
In terms of (1) the professor takes the reader through the calculation of total land area required to generate with photovoltaics the current annual worldwide electrical energy consumption during a year. Here are some quotes:
…you can turn that (16.83 Trillion KWH) into the rate of energy consumption (measured in Watts, just like the world was one big light bulb) by dividing kilowatt hours by the number of hours in a year, and multiplying by 1000 to convert kilowatts into watts. The answer is two trillion Watts, in round numbers. How much area of solar cells do you need to generate this? On average, about 200 Watts falls on each square meter of Earth’s surface, but you might preferentially put your cells in sunnier, clearer places, so let’s call it 250 Watts per square meter. With a 15% efficiency, which is middling for present technology the area you need is 2 trillion Watts/(.15 X 250. Watts per square meter) or 53,333 square kilometers.
That’s a square 231 kilometers on a side, or about the size of a single cell of a typical general circulation model grid box. If we put it on the globe, it looks like this: (black spot marked by the red arrow)…only 0.01% of the Earth’s surface. The bottom line here is that the heat-trapping effect of CO2 is the 800-pound gorilla in climate change.
With respect to geoengineered global cooling (2) the Professor goes on:
...among other things, the presentation (in Levitt’s book) of aerosol geoengineering as a harmless and cheap quick fix for global warming ignored a great deal of accessible and readily available material on the severe risks involved, as Gavin noted in his recent post. The fault here is not that you (Levitt and Dubner) dared to advocate geoengineering as a solution…very few scientists think of it as anything but a desperate last-ditch attempt, or at best a strategy to be used in extreme moderation as part of a basket of strategies dominated by emissions reductions.
Finally, I asked my numbers whiz brother-in-law Maurice Fox to double check Pierrehumbert’s calculations and he pronounced them valid.
Len Bahr (firstname.lastname@example.org)
*Aerosol geoengineering wouldn’t reduce atmospheric CO2, which is acidifying the world ocean. Former VP and Nobel laureate Al Gore appeared on The Late Show with David Letterman on November 4 and the discussion included this phenomenon.
**The Gaia Hypothesis, for example.