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To Stop Climate Change Scientists Propose Blocking Out The Sun (No, Really) April 9, 2011

Posted by Metabiological in Ecology, Science.
Tags: , , ,

Okay lets get a few things out of the way.  Yes, climate change is happening.  The average temperature of the earths atmosphere has been rising quite steadily for…well for as long as we’ve been measuring it.  Yes, we probably have something to do with it.  Atmospheric CO2 has been rising with remarkable steadiness is at least the 1950’s (I chose the 1950’s since that’s when the Keeling Curve measurements began) and that is almost certainly contributing.  Yes, we are now at the point where only a rather drastic restructuring of our society and economy would bring levels back down to where they need to be.

If we assume that these assumptions are correct then we are left with only one conclusion: we’re kind of screwed.  The chance of any substantial changes occurring either at the political or the local level at this point in the game are rather small.  It doesn’t take a psychologist to see that humans generally do not take action on matters with long term consequences until well after its too late.  This conclusion has driven many scientists and politicians to consider alternative solutions to our problem.  What if instead of changing our entire way of life we could come up with a simple technological fix to solve all our problems, thus deluding us into thinking we can continue our ultimately unsustainable lifestyle indefinitely?  Hence, geoengineering.

Geoengineering appeals to people on multiple levels.  As already stated it allows us to continue our current way of life.  It appeals to our vanity by proposing that our ingenuity and genius can overcome any problem.  There’s just one little problem; none of the proposed projects have a chance in hell of succeeding.

Its said that in the kingdom of the blind the one eyed man is king.  Well in the kingdom of crazy geoengineering ideas one idea has come out ahead simply by being less crazy than all the others: blocking out the sun.  No, really.

“There’s the `slippery slope’ view that as soon as you start to do this research, you say it’s OK to think about things you shouldn’t be thinking about,” said Steve Rayner, co-director of Oxford University’s geoengineering program. Many geoengineering techniques they have thought about look either impractical or ineffective…

Those techniques are necessarily limited in scale, however, and unable to alter planet-wide warming. Only one idea has emerged with that potential.

“By most accounts, the leading contender is stratospheric aerosol particles,” said climatologist John Shepherd of Britain’s Southampton University.

The particles would be sun-reflecting sulfates spewed into the lower stratosphere from aircraft, balloons or other devices – much like the sulfur dioxide emitted by the eruption of the Philippines’ Mount Pinatubo in 1991, estimated to have cooled the world by 0.5 degrees C (0.9 degrees F) for a year or so.

Now I want to stress that when it comes to geoengineering I hold no animosity towards the scientists investigating its efficacy or dangers.  This is research that needs to be done unless we want to charge blindly ahead once the danger has come and we have no other choice and good scientists like these people seem to be understand both the practical challenges and the limits of scientific certainty (hint: you are never, ever, EVER certain something will work.)

My problem is that all that scientific skepticism is lost on the public.  To hear this reported on in some circles you’d think it was out panacea, our magic bullet.  “Don’t worry about climate change, we’ll just dump some iron into the ocean and everything will be fine,” and that idea is being exploited by politicians who know damn well that the easiest way to not get elected is to ask people to suffer a little bit now in order to prevent suffering later (e.g. Jimmy Carter.)

Rather than being easy solutions every currently proposed project stands to be both ridiculously expensive, at least partly ineffective and potentially dangerous.  Just as an example lets take blocking out the sun.  While I don’t know the costs off the top of my head (I doubt anyone does) I can only imagine that seeding the stratosphere with aerosol particles would be a massive undertaking.  Keep in mind that since clouds tend to disperse we would need to be constantly reseeding them in order to maintain the cloud cover.  This process would need to be continued until we had managed to bring our CO2 emissions down to a safe level, something which would likely take decades at the least.

Next lets talk about effectiveness.  I’ll grant that increasing cloud cover  would probably lower global temperatures by a fair amount.  Unfortunately it would do nothing to the CO2 already present in the atmosphere.  Unless emissions were leveled off simultaneous will the seeding then as concentrations continue to rise we would need ever more and more cloud cover to counter the increasing effects.  Furthermore it would do absolutely nothing to counter the other big threat of climate change: ocean acidification.  As CO2 dissolves into the sea water it will naturally lower the pH of the world’s oceans with potentially devastating consequences for ocean life.

Lastly there are significant risks to injecting aerosol particles into our own atmosphere.  Let’s not forget that the widespread use of CFC’s, a type of aerosol released by many industries at one time, led directly to the weakening of the global ozone layer and the still-present holes in the layer above Antarctica and the Arctic.

Posts like this make me very angry at myself because when I finish them I always come across as a loom-smashing Luddite demanding we all return to the stone age.  Its not that I think these are idiotic ideas outright only that with a little effort and resources, certainly less than would be required to actually pull off one of these projects, we could largely avert the threat of climate change and render the entire field of geoengineering moot.  Whether we take the necessary steps or not remains to be seen and while I’ve never been optimistic about humanity’s ability to engage in long term planning I haven’t given up hope on us yet.



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