What is Climate Engineering?

What is Climate Engineering?

Climate engineering, also known as geoengineering, describes a diverse and largely hypothetical array of technologies and techniques for intentionally manipulating the global climate, in order to moderate or forestall some of the effects of climate change. In recent years discussions of such approaches have grown considerably amongst scientists, policy-makers, and environmental groups engaged in addressing climate change. A frequent concern is how their development might complement or weaken efforts at mitigation (reducing greenhouse gas emissions) and adaptation (buttressing societal capacities to endure climatic changes).

These technologies may target different areas of the climate system; possess varying mechanics, costs, and feasibilities; have diverse environmental and societal impacts on varying scales; and create their own sets of risks, challenges, and unknowns. They are commonly divided into approaches designed to remove greenhouse gases from the atmosphere (often referred to as greenhouse gas removal technologies, or GGR for short) and approaches designed to reflect sunlight away from Earth (often referred to as solar radiation management technologies, or SRM for short).  

How Did Climate Engineering Research Emerge?

Some propositions for intentionally changing the global climate have existed for decades. However, the last decade has seen an unprecedented proliferation of scientific study along with the creation of dedicated research programs to gauge the physical and social effects  of removing greenhouse gases from the atmosphere and reflecting sunlight back into space. Scientific work has been accompanied by increased attention from the media, public intellectuals, and environmental and technology watchdog groups. Government-commissioned assessment reports have been released by the UK, the US, and Germany. International governance frameworks for field research are being created at the Convention on Biological Diversity and the London Convention and Protocol. The Intergovernmental Panel on Climate Change has substantially expanded its discussion of climate engineering in its fifth assessment report, compared to earlier reports.

Risks, Unknowns, and Challenges

For now, the field of climate engineering consists of desk and laboratory studies and small-scale field research on some of the proposed methods. No technologies have been deployed at a scale that impacts the global climate. Yet, the intent behind climate engineering, its geographically large or even global impact, and the complexity and uncertainty of its potential effects upon climate governance – and human society – raise profound questions.

On a basic level, there are technical questions about the costs and feasibility of development and deployment of various technologies, as well as the geophysical processes that they aim to manipulate. Given our imperfect knowledge of both the technologies and the climate system, there are worries about unintended environmental and ecosystem side effects. Even if the technologies function as intended, they will not “turn back the clock” from a climate influenced by rising greenhouse gas emissions to a previous climate – an engineered climate will be a new and different one.

Climate engineering arises in a highly complex social and political context. Potential for unilateral deployment of swift-acting methods, such as the injection of reflective particles in the atmosphere to screen the sun, raises concerns of reckless pursuit of self-interest by powerful actors. One of the strongest fears is that developing climate engineering technologies may siphon resources and momentum away from already flagging efforts to reduce carbon emissions, and that this would disrupt negotiations at the UNFCCC. Others criticize what they see as the postponing of transitioning off fossil fuels to later generations, the unequal capacity between states to research and deploy the technologies, or shifting the effects of what would have been GHG-driven climate change to countries and demographics that will suffer from the changed environmental conditions that result from engineering the climate. The physical impacts of climate engineering – both intended and unintentional – may alter natural surroundings and weather patterns as well as the lives and livelihoods dependent upon them. At an overarching level, others question how climate engineering alters (or confirms) humanity’s relationship to the environment in the Anthropocene, as well as the hubris (or ingenuity) of applying technological solutions to complex issues. The wisdom of climate engineering at a moral and ethical level is contentious among scientists, and will likely continue to be so as discussions of the topic increasingly reach beyond the scientific realm.

It is still an open question as to whether the risks of climate engineering outweigh the risks of climate change, or how climate engineering might be integrated with existing climate policies. Much discussion dwells on how to frame, explore, research, and perhaps even deploy these technologies under conditions of high uncertainty – in essence, that decisions on climate engineering have to be made despite the fact that we cannot know the exact unfolding of an engineered climate beforehand, and that it may or may not be more disruptive than the effects of a warming world with rising emissions. Indeed, it is likely that we will never retrospectively know which climate is preferable, given the uncertainty in climate models, the difficulties in detecting and attributing climatic changes, and the resulting difficulty of constructing a convincing counterfactual.

Critical Global Discussions

The complexity of the issues associated with engineering the climate presents a challenge for shaping even the most basic research and engagements with the public and policy-makers today. It is difficult to predict how the debate on climate engineering will influence – or be influenced by – future developments in technology, the climate system, or the international order.

Hence, efforts to probe the boundaries of the discourse – and their effects upon the public imagination – are still evolving. Although research, engagement efforts, and media coverage are growing, they are still largely limited to a handful of countries and actors in the global North. Visions and risks of a climate-engineered future are imagined scenarios extrapolated from early developments or from previous debates on novel technologies (e.g. nanotechnology or genetic engineering) by small networks of academics, practitioners, and journalists. Early governance frameworks that are being generated in international negotiations and by the academic community remain untested. Even the terms of reference of the debate undergo periodic questioning, with researchers proposing alternative labels and categories for the solar and carbon-targeting suites of climate engineering technologies.

How can we explore a social and technological imaginary, whose discussion might be deemed necessary by some, but will have far-reaching impacts across the global community? Acknowledging  that climate engineering intersects with other fields and larger trends in all geographic regions and at all levels of governance suggests that the global community must develop an understanding of the social, environmental, cultural, political and ethical issues involved. In order to determine whether any climate engineering approach is appropriate as an effort to address climate change, we must first enter into critical global discussions.


The Royal Society (UK)

Geoengineering the Climate: Science, Governance and Uncertainty (2009)



Solar Radiation Management Governance Initiative

Solar Radiation Management: the Governance of Research (2011)



The Bipartisan Policy Center’s Task Force on Climate Remediation Research (US)

Geoengineering: A National Strategic Plan for Research on the Potential Effectiveness, Feasibility, and Consequences of Climate Remediation Technologies (2011)



House of Commons Science and Technology Committee (UK)

The Regulation of Geoengineering (2010)



Congressional Research Service (US)

Geoengineering: Governance and Technology Policy (2010)



United States Government Accountability Office (US)

A Coordinated Strategy Could Focus Federal Geoengineering Research and Inform Governance Efforts (2010)



United States Government Accountability Office: Center for Science, Technology, and Engineering (US)

Climate Engineering: Technical Status, Future Directions, and Potential Responses (2011)



The Federal Ministry of Education and Research (Germany)

Large Scale Intentional Interventions into the Climate System? Assessing the Climate Engineering Debate (2011)



IPCC Expert Meeting on Geoengineering (Lima, Peru, 20-22 June 2011)

Meeting Report (2012)



European Transdisciplinary Assessment of Climate Engineering (EuTRACE)

Collaborative project of 14 partner organizations from Germany, UK, France, Austria and Norway, to explore a European perspective toward climate engineering



Climate Geoengineering Governance (CGG)

Collaborative project between Universities of Oxford and Sussex, and University College London to provide a basis for the governance of geoengineering methods



Deutsche Forschungsgemeinschaft / German Research Foundation (DFG)

DFG Priority Program for projects exploring ‘Climate Engineering: Risks, Challenges, Opportunities?’




News-aggregator website for all publications and projects on climate engineering



Geoengineering Google Group

Forum for the discussion of all climate engineering topics, and for updates on projects and publications