Read Part One of “Our Broken Sky” here.
In 1992, the National Academy of Sciences defined geoengineering as “large-scale engineering of our environment in order to combat or counteract the effects of changes in atmospheric chemistry,” including the build-up of greenhouse gases like Carbon Dioxide (CO2).
But that was not the first time human beings thought about how to fix what they knew would break. For that we have to count back eight American presidents to Lyndon Johnson in 1965.
That year the Environmental Pollution Board of the President’s Science Advisory Committee warned that “by the year 2000 there will be about 25% more CO2 in our atmosphere than at present [and] this will modify the heat balance of the atmosphere to such an extent that marked changes in climate … could occur.”
In response Johnson gave a “Special Message” to Congress: “This generation has altered the composition of the atmosphere on a global scale through … a steady increase in carbon dioxide from the burning of fossil fuels.”
What Johnson didn’t mention was that this distinguished group of scientists anticipated our massive failure and suggested methods to geoengineer our way out of the climate catastrophe they saw coming.
Forty-three years later in a Scientific American article in 2008 we were told, “Geoengineering schemes fall into two categories, corresponding to the two knobs you might imagine twiddling to adjust the earth’s temperature. One knob controls how much sunlight — or solar energy, to be more precise — reaches the planet’s surface; the other controls how much heat escapes back into space, which depends on how much CO2 is in the atmosphere.”
In a paper published in Atmospheric Chemistry and Physics in January of 2009, the authors wrote, “By 2050, only stratospheric aerosol injections or sunshades in space have the potential to cool the climate back toward its pre-industrial state.”
The paper referred to two proposals for reflecting solar radiation back to space: adding “sulfate aerosol” or “manufactured particles” to the stratosphere. The authors wrote, “Adding such aerosols to the troposphere has been ruled out due to negative impacts on human health, the greater loading required than the equivalent intervention in the stratosphere, and the need for multiple injection locations. However, increasing the reflectivity of low level marine stratiform clouds by mechanical or biological generation of cloud condensation nuclei (CCN) is being considered.”
While they concluded by stating “climate geoengineering is best considered as a potential complement to the mitigation of CO2 emissions, rather than as an alternative to it,” they wrote that “a number of geoengineering options show promise … most promisingly stratospheric aerosol injections.”
They also wrote, “mechanical enhancement of marine stratiform cloud albedo could achieve a patchy or partial cancellation of mitigated CO2 radiative forcing.” However, these methods “carry a heavy burden of risk because they have to be continually replenished and if deployment is suddenly stopped, extremely rapid warming could ensue.”
Watch for Part Three of “Our Broken Sky” next week.
Doug Craig earned a B.A. in journalism during the Carter administration and a doctorate in psychology during the Reagan administration. He has been a clinical psychologist in Redding for 22 years. Since 2004 he has suffered a serious obsession with the science of climate change and is most concerned about the Earth his children will inherit. You can find him at his website, ClimateTruth.org.
