Posted by: ericgrimsrud | April 20, 2015

Will we be trying Solar Geoengineering soon?

We are  now aware of a relatively simple way to compensate for the warming effects of our increasing levels of greenhouse gases.  It is called “solar engineering” and is accomplished by blocking a portion of our incoming solar radiation.  A simple way to do this is to mimic very large volcanic eruptions that inject sulfur dioxide into the stratosphere.  Once there, SO2 molecules go on to form particulate matter and these particles increase the reflection of incoming solar radiation back into outer space.  Most of these sulfate particles will stay in the stratosphere for a year or two. Thus, a continuous flow of SO2 added to the stratosphere  via high altitude aircraft could established any level of light reflection and cooling desired.  And this scheme could be adopted with relatively little cost.

So will we be using this scheme any time soon? Since the answer to that question might soon  become affirmative, it is imperative that we carefully consider and be prepared for any potential problems that might accompany this scheme.  Most of the anticipated problems will fall into one of two types – one concerns the science involved and the other, the politics.

Concerning the science, the questions are of the “unintended consequences” nature.  For example, will these added sulfate particles have any effect on the ozone layer of the stratosphere?  We need a healthy ozone layer in order to screen out incoming ultraviolet radiation.  Also, what will be the effects of this scheme, if any, on local weather and precipitation patterns?  So far, scientific “experiments” have only been done via computer models but that research has been encouraging.  Another advantage of this scheme is that the sulfate particles could be removed by natural processes whenever we wish by discontinuing SO2 injection.  A great deal of additional research concerning this scheme is presently underway as we consider using it.

Even if the science continues to look satisfactory, however, a great deal of thought concerning the politics involved must also be considered.  Some of the anticipated problems will revolve around the question of “what is the right temperature for the Earth?”  One’s answer to this question is likely be depend very much on where you live.  High latitude countries of the  Northern Hemisphere are likely to prefer higher temperatures than those closer to the Equator.  Pakistan, for example, is in urgent need of lower temperatures and lower sea levels while Russia is not.  If we find that local weather patterns are affected by SO2 injection, then some countries might have to endure more sacrifice than others for the good of the entire planet.  Requests for international compensation in the form of financial assistance and/or population relocation would be sure to follow.

David Keith of Harvard University (formerly at the University of Alberta in Calgary) is a leading expert in the field of geoengineering whose work I have followed for many years. Through his interactions with all regions of the world, he is well aware of the political as well as scientific issues that will have to be faced if we pursue this scheme. Thus, I found his recent Washington Post opinion on this topic to be most informative.  You can see it at

Upon reading about this and other geoenginering schemes, one is initially inclined to say “no way!, we should not do untested experiments such as these on the only planet we have”.  On the other side of that argument, however, is the equally sobering thought, “what other choices do we have?”   Even if we halted all greenhouse gas emissions today, we still can expect to experience extensive warming and degradation of existing civilizations during the next several centuries.  In addition, CO2 emission rates continue to increase every year so that the background level of CO2 increases about 2 ppm per year.  By mid century, our atmosphere will contain well over 470 ppm CO2 if we continue on our present course.

Thus, we presently find ourselves between a rock and a hard place.  In retrospect, of course, we should have listened to James Hansen’s testimony to Congress way back in 1988  (see that testimony at ).  We did not heed his warning, however, and have still not heeded it 27 years later – as CO2 emission rates continue to rise.  Oh what a web we weave in our mindless pursuit of  short-term wealth.

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