(note: In part 3 of our series, we present more excerpts from ozone expert Dr. Paul Crutzen's essay on his detailed plan to fight global warming.)
Part 1,Part 2
ALBEDO ENHANCEMENT BY STRATOSPHERIC SULFUR
INJECTIONS: A CONTRIBUTION TO RESOLVE A POLICY
DILEMMA? Pt. 3
An Editorial Essay
Researchers at the Lawrence Livermore Laboratory are so far the only ones who have modelled the stratospheric albedo modification scheme.
In a first study, Govindasamy and Caldeira (2000) simulated this by reducing the solar luminosity by 1.8%, to balance future climate warming by a doubling of CO2.
Although solar radiative forcing has a different physics and spatial distribution than the infrared effects caused by CO2, the model results indicated that the global temperature response by both perturbations at the Earth’ surface and atmosphere largely cancelled out.
Although these preliminary model results would be in favor of a stratospheric sulfur injection operation, the required annual S inputs are large, so that the possibility of adverse environmental side effects needs to be fully researched before the countermeasure to greenhouse warming is attempted.
What has to be done first, is to explore whether using a sulfur injection scheme with advanced micro-physical and radiation process descriptions will show similar model results as the simple solar luminosity adjustment scheme of Govindasamy and Caldeira (2000).
Further studies,following those conducted by Govindasamy (2003), should address the biological effects of the albedo modification scheme.
As already mentioned, injection of soot may be an alternative, but in need of critical analysis.
Such studies by themselves, even when the experiment is never done, will be very informative.
Among possible negative side effects, those on stratospheric ozone first spring to mind.
Fortunately, in this case one can build on the experience with past volcanic eruptions, such as El Chich´on in 1982 and Mount Pinatubo in 1991, which injected 3–5 Tg S, and 10 Tg S, respectively, in the stratosphere.