Three points for the great debate on climate engineering

By Mark Lawrence (Scientific Director, Institute for Advanced Sustainability Studies)

The CEC14 will bring together a wide range of people interested in learning more about and critically discussing the issue of climate engineering. Participants will hail from every continent (except Antarctica), and will include researchers from a very wide range of disciplines and stakeholders from various sectors.  We expect this diversity to lead to rich discussions, especially because experts from all corners of the problem will be available to provide well-informed input into the discussions.

This thirst for cross-disciplinary exchange has been evident to me for several years in dialogue around this topic, and I was reminded of this again at the “Great Debate on Geoengineering” at the European Geosciences Union (EGU) General Assembly, held in Vienna on May 1st, 2014.  Over 500 geoscientists attended, and the discussion was very lively. Remarkable was the fact that about 2/3 of the questions that were asked to the panelists were not about the natural science aspects of the various proposed climate engineering techniques (which was the central expertise of the panel), rather about the many economic, psychological, ethical, political, legal, and other aspects. As a result, the EGU is likely to invite representatives of these fields as participants in future such events. 

The debate can be viewed here. A news item is available here, and an article on the event was published in the American Geophysical Union’s newspaper, EOS, available here.

For the opening to the Great Debate, I prepared a statement with three main points describing what I think it is important to keep in mind when discussing climate engineering. I think this statement can also serve as a useful input for helping to frame the critical discussions at the CEC14, so I’m providing it here:

First, I’d like to point out that it is of great importance in discussions around climate engineering to distinguish carefully between, on the one hand, the proposed measures to remove CO2 from the atmosphere, commonly called “carbon dioxide removal” or CDR, and on the other hand, the proposed measures to modify the Earth’s radiation budget, commonly called “solar radiation management” or SRM. 

This is due to the vast differences between CDR and SRM techniques, so that blanket statements applied to climate engineering often really only apply to one of these broad approaches, and can thus be misleading and counterproductive. The same point also applies to the subset of techniques within CDR and SRM, where there are also vast differences, for instance between biochar production and ocean fertilization.

This point is well-known by much of the research community, and is mentioned repeatedly in discussions and various publications and assessments. Nevertheless, it is proving difficult for us to follow our own good advice, and most of the community – including me – still falls into the trap of generalizing too much. 

So I would encourage more care and effort in making the distinctions clear.

Second, I think it is important to emphasize at the outset that, based on an assessment of the current state of knowledge, for all of the proposed techniques to remove CO2 from the atmosphere, very long timescales – generally decades – would be needed before a significant impact on the global atmospheric CO2 concentrations could possibly be achieved. 

For many of the techniques, this is due to the large infrastructure that would be needed – comparable for example to the size of the oil industry – associated with large energy requirements. For others it is due to limitations in various ecosystems – and for most of these there are also potentially significant side effects that need to be considered. There are also uncertainties in the total storage capacities. 

Nevertheless, given the daunting consequences of ever-increasing atmospheric CO2 concentrations, it is worth continuing to investigate and develop the potential for carbon dioxide removal, but it is important to make clear that this is done from a long-term perspective; we cannot count on proposed CDR measures to notably supplement mitigation measures in the near future.

Techniques to modify the Earth’s radiation budget, if they were implemented, would act much more quickly to cool the planet – on the timescale of a year or less.  However, they harbor very large uncertainties about their potential effectiveness, especially the varying regional distribution of effects on temperature and precipitation, and about a palette of potential side effects.

Thus, even though it might be possible within a decade to develop and implement the technological capability to modify the Earth’s radiation budget on a global scale, it would take decades – if it is ever possible at all – to be able to do so in a knowledgeable, informed, and just manner, not only in terms of the physical consequences, but also in terms of the ethical implications and the challenges of international governance that would need to be addressed.

And the third point I would like to make picks up exactly here: although geoscientists are best able to investigate and understand the implications for the physical, chemical, and biological Earth System, it is important that those who choose to address this issue in scientific studies do not lose sight of the vast range of societal issues that are associated with both CDR and SRM – and not only with the possible future implementation of any of the various techniques, but also associated with even conducting research and dialogue about these topics. 

The most well-known among these concerns is the so-called “moral hazard”, the risk that giving the impression that a “Plan B” is being worked on and will soon be available will reduce the motivation to implement mitigation measures. 

Though the verdict is still out on this and other such concerns, which need further empirical social research, the concerns are very far-reaching – extending all the way to our understanding of what humanity is, and its role in an Anthropocene which may someday shift from having largely unintentional and uncoordinated global impacts to a coordinated, intentional modification of the Earth System on a global scale. Even if the geoscience research may someday provide extensive insights into what the various climate engineering techniques would mean for the Earth System, will we ever really understand in turn what engineering the climate of the Earth System would mean for humanity itself?