Key words :
carbon dioxide removal,
copenhagen climate conference,
solar radiation management
Geoengineering the climate : science, governance and uncertainty
23 Sep, 2009 03:17 pm
Earlier this month, the Royal Society of the UK issued a report entitled "Geoengineering the climate : science, governance and uncertainty". Ken Caldeira, the director of the Caldeira Lab at the Carnegie Institution in the U.S. and a member of the working group involved in producing this report, answers Scitizen's questions.
The report divides geoengineering methods into two basic classes. Can we put Carbon Dioxide Removal methods (which remove CO2 from the atmosphere) on the same level as Solar Radiation Management methods (that reflect a small percentage of the sun's light and heat back into space) yet?
No, Carbon Dioxide Removal methods and Solar Radiation Management methods are two very different kinds of interventions. I was originally arguing that the Carbon Dioxide Removal methods should not even be in the report because I do not consider them geoengineering.
Carbon Dioxide Removal methods add no new climate risk (although they can add other types of new environmental risk). Carbon Dioxide Removal is basically the reverse of carbon dioxide emissions. In general, these methods work slowly but address the root cause of the problem.
Solar Radiation Management methods add new climate risk, but hold out the potential of reducing overall climate risk. Some Solar Radiation Management methods can work rapidly and thus may be of use in the event of a climate emergency or climate crisis. I think this "climate emergency response" possibility is the most important reason we need to pursue research into these options.
Taking into account the risk of significant side effects, would you call geoengineering "a necessary evil"?
I think that the assortment of options considered in the report are so diverse that one cannot generalize across all of them. I hope we are smart or lucky enough to avoid a climate catastrophe that would induce us to want to put sulfates in the stratosphere or resort to other similar desperate measures. I think of these as a toolbox full of tools. A powersaw can be used for evil or for good.
The goal of these proposals is to reduce overall risk and damage. If we have high confidence that some option would reduce overall risk and damage then it would probably make sense to deploy that option. Without this confidence, deployment would likely be unwise.
Without large-scale field testing, what did you base your evaluation on?
Our evaluation was based on paper studies, computer model simulations, and order-of-magnitude basic calculations.
How to elude the moral hazard argument, namely the fact that geoengineering might be used as an excuse not to cut greenhouse gas emissions?
I believe that recognition and admission that our greenhouse gas emissions are increasing the likelihood of a climate crisis that would push us to consider desperate measures would tend to encourage us to work harder to diminish emissions. If you are not concerned about a climate crisis, you neither reduce emissions nor develop plans for what to do should a crisis occur. If you are concerned about a climate crisis, you both reduce emissions and develop plans for what to do should a crisis occur.
According to you, what should thereof be the place of geoengineering at the Copenhagen Climate Conference in December?
I see no reason for the Solar Radiation Management options to be considered in December. Some Carbon Dioxide Removal methods (such as planting trees) will be considered in Copenhagen. The "ultimate objective" of the UNFCCC is "to achieve... stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system." Carbon Dioxide Removal methods are relevant to stabilizing greenhouse gas concentrations, but Solar Radiation Management options are not particularly relevant in this context.
Interview by Clementine Fullias
Download the report
Ken Caldeira is a scientist who works at the Carnegie Institution for Science's Department of Global Ecology. The Caldeira Lab conducts research to try to improve the science base needed to allow human civilization to develop while protecting our environmental endowment. It includes ocean adification, climate and emissions and climate intervention ('geoengineering').
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