Solar Radiation Management


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Opinion Piece
2010 (pdf)


In 2010, IRGC published an opinion paper by Granger Morgan (CMU) on the need to engage in research and some experimentation about solar radiation management (SRM): Cooling the earth through solar radiation management: the need of research and an approach to its governance. Strategies to modify the albedo could quickly cool the planet’s surface, but environmental and other risks are not well understood.

Today, we still believe that most of the efforts must be put on reducing greenhouse gas emissions, but we also believe that it would be a mistake not to engage in a scientific research programme about SRM. Safe and small-scale experiments could build trust and governance.

Early work done by IRGC in 2009-2010 contributed thinking to two pieces just published and available below:

  • Jane Long, Fank Loy and Granger Morgan in Nature (5 February Vol. 518) on Start Research on climate engineering. The authors suggest that a research programme should be collaboratively designed in such a way that is has social value as well as scientific benefits, it adopts a risk view, transparency is guaranteed, vested interests are identified and do not bias evaluation, and regulatory frameworks are established.
  • US National Research Council on Climate intervention: Reflecting sunlight to cool earth


IRGC project 2009-2010


Cooling the Earth Through Solar Radiation Management

Climate engineering – a term which is increasingly used to describe a number of technologies which can have the potential to offset the global warming caused by greenhouse gases (GHG) – raises many risk governance issues.

Some of these issues concern the technologies themselves, and their impacts. One is that there is no single climate engineering technique. Another set of issues derive from limited knowledge. Climate modelling is itself hugely complex and imprecise, and it is currently not possible to adequately model the effects of climate engineering technologies on not only the Earth’s climate but also other parts of the biosphere. The need for such research raises issues of how (under what norms) the research is conducted, by whom and under whose oversight. It may be premature to introduce new legal frameworks for technologies that have yet to be tested, but there may well be a need to develop a transparent approach to ensuring the legitimacy and purpose of the necessary research.

Scientific evidence indicates that rigorous measures are needed to reduce GHG emissions and their impact. These measures are known to be hugely expensive and their effect on global warming will be slow. Climate engineering could be seen by some as a potentially cheaper policy alternative. The moral hazard is that a decision to support climate engineering technologies could lessen efforts to reduce the global concentration of CO2 and other greenhouse gases.


To help progress discussion of these issues, an expert workshop was held at the Calouste Gulbenkian Foundation in Lisbon, Portugal on 20 and 21 April 2009. Attended by experts from science, business and governments, from North and Central America, Europe, Russia and China, the discussion was held under Chatham House Rules in order to encourage free discussion of geoengineering’s many risk governance issues.

The workshop was convened by the Portuguese Ministry for Science, Technology and Higher Education together with the Portuguese Science and Technology Foundation, The Calouste Gulbenkian Foundation and the International Risk Governance Council and organised in close cooperation with the Carnegie-Mellon Portugal Program, the National Science Foundation Climate Decision Making Center at CMU and the Energy and Environmental Systems Group of the University of Calgary.

Climate Engineering – Opinion Piece

This opinion piece, a first of its kind for IRGC, was written for IRGC by Prof. Granger Morgan (Chairman of IRGC’s Scientific and Technical Council and Head, Department of Engineering and Public Policy, Carnegie Mellon University) and Katharine Ricke (Doctoral Candidate at the Department of Engineering and Public Policy, Carnegie Mellon University).

The world needs to achieve roughly an 80% reduction in emissions of CO2 in order to avoid a significantly changed and warmer climate, and this reduction is predicted to be slow and costly. In contrast, if the fraction of sunlight reflected by the earth back into space (the albedo) is slightly increased, then the planet is cooled. Activities that increase earth’s albedo are called “solar radiation management” or SRM. While SRM may be relatively cheap and fast, it is also imperfect. It is controversial because it does not target the root cause of climate change, i.e. greenhouse gas emissions.

Donald Johnston (IRGC Chairman, 2010) notes in the foreword to the IRGC paper, SRM “may indeed be inevitable as a last resort,” and the authors argue that in order to be prepared in the event of a “climate emergency”, or for the case where someone tries to undertake SRM unilaterally, now is the time to establish an internationally coordinated, open research programme on SRM. They suggest:

  • Research community should define a set of limits within which modest low-level field research could be conducted with minimal impact; and
  • Effort should be undertaken to engage the foreign policy community in discourse to identify alternative possible approaches to the global governance of SRM and assess their strengths and limitations.