Climate 2.0 – Can Geoengineering Make the World a Safer Place?

Wizardry to some, anathema to others, geoengineering—or climate engineering—is slowly encroaching on the territory of traditional climate policy. The Intergovernmental Panel on Climate Change’s (IPCC) next Assessment Report, due in 2013/14, will cover “the deliberate large-scale manipulation of the planetary environment”[1] as a potential strategy to counteract man-made climate change. Technological solutions are increasingly seen as a necessary complementary strategy to mitigation and adaptation to contain the worst impacts of climate change. They may well be risky; but if the global transition to a low-carbon economy comes too late and we therefore face an increase in global average temperatures by 4 degrees Celsius by the end of the century, technology could potentially be the proverbial last straw. The attitude toward geoengineering differs considerably among scientists and climate policymakers in the U.S. and Germany, and this article will demonstrate why this is the case. It first explains the main approaches to geoengineering as well as their respective risks and then discusses the perceptions of geoengineering in the U.S. and Germany, respectively. Finally, the article explains the need for an international research agenda on geoengineering.

What is Geoengineering?

Geoengineering is not new. It was first mentioned in a 1965 report entitled “Restoring the Quality of Our Environment,” which was prepared for then-president Lyndon Johnson. Yet it was not until forty-five years later that geoengineering gained further attention. Over the past two years or so the possible failure of international climate negotiations and increasing evidence for an acceleration of climate change have alarmed many in the international climate science and climate policy communities. Geoengineering is therefore now increasingly being looked into as a kind of “insurance policy” should “conventional” climate policy fail.

Today, there are two broad approaches to geoengineering. The first is a manipulation of global temperatures through direct interference with the earth’s radiation balance. This is known as Solar Radiation Management (SRM). If we can reduce the amount of solar radiation hitting the earth, the ensuing cooling effect would alleviate some of the impacts of climate change. One way of bringing about such an effect could be the artificial brightening of clouds over the oceans. Solar radiation can also be manipulated by dispersing sulphur particles in the stratosphere at a height of 15 to 50 kilometers, for instance with the help of airplanes. These particles or aerosols would then block parts of the sunlight and prevent it from reaching the earth. The effects are much like those of a volcanic eruption: when the Pinatubo in the Philippines erupted in 1991, global temperatures decreased by about 0.5°C for one year due to the sulfur dioxide in the atmosphere. So why not bring about the same effect in an artificial manner?

An alternative approach to geoengineering, Carbon Dioxide Removal (CDR), consists of an interference with the earth’s carbon cycle. Since surplus CO₂ is one of the biggest culprits of climate change, extracting CO₂ from the atmosphere and sequestrating it in geological formations or on the ocean floor could help contain some of the worst consequences. Some of the approaches to CDR that are being discussed at the moment are outright uncontroversial. They comprise reforestation and afforestation or improved land-use management to enhance the ability of soil to store carbon dioxide. Another, more contentious, method is the fertilization of oceans with iron to stimulate the growth of algae. The objective is for the algae to absorb CO₂ and sequestrate it deep in the ocean when they die. Whether or not it is possible to store CO₂ indefinitely has not been determined yet, though.

In principle, both geoengineering approaches sound logical at first glance. And to a small group of experts in the international climate research community, such as Ken Caldeira at Stanford or David Keith at Harvard, they have significant appeal. Yet the great majority of scientists and policymakers warn against geoengineering or consider it as outright crazy because of the risks involved. Proponents argue, however, that it might soon be necessary to balance the risks of climate change against the risks of geoengineering as an instrument of last resort should the global transition to a low-carbon economy come too late. This does not mean that geoengineering should at any point in time replace ambitious policies to reduce greenhouse gas (GHG) emissions. After all, a de-carbonization of the economy has additional benefits such as the creation of new jobs and markets in the cleantech and renewables sectors, increased food, water, and energy security, and hence more global stability. Nevertheless, the risk of tipping points in the global climate system justifies the in-depth study of geoengineering technologies. Once a certain threshold of CO₂ and other GHG in the atmosphere is reached, tipping elements can be triggered that make climate change an irreversible process. Among these tipping elements are—as remote as they might still seem—the melting of the Greenland ice sheet and Arctic sea ice loss.

Geoengineering and Its Discontent

A risk perspective is especially relevant in the case of SRM because the deliberate manipulation of solar radiation is particularly rife with risk. SRM measures have a significant impact on atmospheric circulation, so there will be winners as well as losers. For instance, those regions of the world that are already affected the worst by draught—such as the Sahel zone—could be affected disproportionately by SRM measures as well and suffer even more damage. Additional crop failures in the region, brought about by geoengineering projects elsewhere on the planet, could prove disastrous and trigger humanitarian catastrophes as well as large migration movements. Any serious consideration of the use of SRM measures therefore has to take the potential consequences for other regions into account if conflict over these measures is to be avoided.

A further critique of SRM is that it resembles a band aid approach to climate change: it does not stop the increase of CO₂ and other GHG in the atmosphere or the acidification of the oceans—a major threat to the food chain and, hence, to human beings. SRM is therefore a typical case of the moral hazard challenge. Many in the climate community fear that having the technology to contain climate change without an accelerated de-carbonization of our economies available might discourage policymakers to implement and enforce rigorous climate policies. What is more, SRM would have to be permanent to have effects. Stopping SRM could prove disastrous since the accumulated carbon in the atmosphere could wreak havoc in the climate system and bring about sudden catastrophic warming once the “band aid” is removed.

Unfortunately, the actual potential—or danger—of SRM can only be determined with considerable difficulty as it is close to impossible to do any field testing on SRM. “Testing” SRM would be equivalent to “doing” SRM because we cannot test the impact of SRM measures in a very small portion of the atmosphere and then scale up the results. This makes it difficult to account for all the possible side-effects of SRM to the earth system as well. Equally, there is a lot of uncertainty around the costs of different SRM technologies.

In contrast to SRM, CDR is much less controversial but it would also take much longer for CDR methods to take effect. The environmental impacts, the safety, and the effectiveness of different CDR approaches have not been determined yet. The 2009 Lohafex project, conducted by German researchers from the Alfred-Wegener-Institute, illustrates the uncertainties around geoengineering in general and CDR in particular.  The project consisted of fertilizing parts of the ocean in the southwestern Atlantic with iron to stimulate the growth of algae. To the surprise of the scientist, however, copepods, tiny shrimp-like crustaceans, considered the surplus algae as a welcome supplement to their habitual diet, which brought about the failure of the Lohafex project: the amount of algae available to absorb any CO₂ was negligible in the end and demonstrated in unmistakable terms just how little we know about the earth system and our possibilities to reverse the negative impacts of accelerating changes in the global climate.

Perceptions of Geoengineering in the U.S. and Germany

The failure of the Lohafex project should not precipitate the end of all geoengineering research, however. On the contrary, more research is necessary to determine with some degree of certainty whether we do have the option to contain climate change through the use of technology. This view does seem to have appeal on the western side of the Atlantic. In Germany, however, research and policy still seem to be governed by a rejection of geoengineering out of principle rather than healthy skepticism.

A number of think tanks in the U.S. —such as the Woodrow Wilson International Center for Scholars, the Bipartisan Policy Center, and the American Enterprise Institute for Public Policy Research—but also the U.S. Government Accountability Office and the U.S. House Science and Technology Committee, have already published comprehensive reports on geoengineering in an attempt to provide policy guidance on the issue. These reports do not reflect any sense of “hubris,” and not even a can-do attitude; they do, however, point at the possible inevitability of focused research on SRM and CDR as well as the regulatory challenges that geoengineering poses at the international level. As the Bipartisan Policy Center’s report “Task Force on Climate Remediation Research” argues, “[m]anaging risks is a central principle of effective climate policy”—this perspective should inform the German research agenda on geoengineering as well.

Despite the fact that Germany is already home to a considerable number of research projects on geoengineering—consisting of computer simulations and modelling but also exercises in ethical and regulatory analysis—scientists and policymakers alike shy away from a public debate on the subject matter. The justified concern that a debate on geoengineering could divert attention and resources from conventional mitigation goals is overshadowing the need to face the debate head on.

Just in the end of 2011, the Department of Science and Education of the German federal government published one of the most comprehensive reports on geoengineering available worldwide: “Targeted Climate Interventions? An Overview of the Debate on Climate Engineering” (Gezielte Eingriffe in das Klima? Eine Bestandsaufnahme der Debatte zu Climate Engineering) provides a thorough analysis of all geoengineering approaches, their risks and opportunities, as well as the ethical and legal dimension of the subject matter. It is up to policymakers now to build on the report and launch an informed debate domestically to prepare Germany for the international debate that will certainly commence once the IPCC’s next Assessment Report is published.

One could argue that the prevailing risk-averse attitude reflects the more “conservative” bias in the German bioethics debate: whether discussing genetically modified organisms, stem cell research, or synthetic biology, German public opinion is usually cautious when humans are attempting to interfere with natural or biological systems. The lack of official support for a public debate on geoengineering by the federal government, political parties, or other actors in public policy can be explained by several factors. First, Germany’s role in international climate diplomacy and the domestic challenges of the energy transformation (Energiewende) do not allow much room for discussing technological solutions for the risks of climate change. There might also be concerns that a debate could squander Germany’s hard-earned credibility in international climate negotiations. Another reason why there is currently no debate might be the lack of political entrepreneurship. After all, the time and effort that are necessary to discuss emissions targets, energy efficiency programs, and the Energiewende at large do not leave much room for additional points on the climate policy agenda. Championing geoengineering as a third approach when combating climate change does not exactly seem to enhance the career prospects of scientists or to win elections in the case of politicians.

As an April 2012 position paper by the Deutsche Forschungsgemeinschaft, DFG (German Research Foundation) explains, most German scientists researching geoengineering demand that new or improved mechanisms to intervene in the earth’s climate system be not a priority in climate science. Yet the paper also argues that German researchers can make important contributions to the international debate on geoengineering, in particular as far as possible social and economic consequences, negative side effects, as well as ethical questions such as inter-generational responsibility for the planet are concerned. Moreover, the position paper states that Germany could offer interdisciplinary and regulatory perspectives on geoengineering and that German scientists could legitimately warn against too much optimism considering just how little we know about geoengineering and the climate system at large. It is clear that, as a key player in international climate policy and diplomacy and as one of the most significant countries in climate research, Germany can hardly sit on the fence in the nascent international debate on geoengineering.

Toward a Geoengineering Research Agenda?

Given the complexity of different risks that have to be balanced against each other and the controversies surrounding geoengineering international research efforts have to be coordinated as soon as possible. A lot is happening already, for instance in the context of the European Trans-disciplinary Assessment of Climate Engineering (EuTRACE) which is coordinated by the Institute for Advanced Sustainability Studies (IASS) in Potsdam, Germany. Scientists from Germany, the UK, Norway, France, and Austria are collaborating to assess the potential benefits and perils of geoengineering in an international and interdisciplinary context. But we still need both binding rules on the conduct of geoengineering research and transparency with regard to the research programs in different countries. Uncoordinated research would not only be a waste of resources; it could also raise suspicions of a planned unilateral deployment of geoengineering technologies with dire consequences for other regions of the world.

The real risks of geoengineering can only be known through extensive interdisciplinary research and scientific exchange across countries. To this day, the actual extent of potential impacts, opportunities, risks, and costs of geoengineering is unknown. This is why comprehensive and independent technology assessments and an international regulatory framework for geoengineering research are indispensible. It is essential to find out whether there is actually a “plan B” for the containment of climate change—or not. Starting such an exercise when tipping points in the climate system have been triggered already is not an option. In this case, time won’t be on the side of scientists and they might even come under pressure to produce favorable research results—whether or not geoengineering techniques have been proved safe for use. Against this background, the position paper by the DFG singled out the right priority in future geoengineering research in Germany: research to determine the possible consequences of different geoengineering techniques and the need for concomitant technology assessment.

At the same time, the risks surrounding the research and potential deployment of geoengineering technologies have to be balanced against the risks of uncontained climate change and a failure of conventional mitigation policies. Uncertainty about the future development of global average temperatures and the possible economic, social, and security impacts of climate change cannot be an excuse for neglecting research on geoengineering.  Responsible climate policy will have to account for the possibility that we might not be able to contain the increase in global average temperatures to 2°C. Although the reduction of GHG emissions will have to remain the policy priority and must not be compromised under any circumstances, alternative strategies have to be designed in parallel. Those alternative strategies comprise, first, adaptation to a world where global average temperatures have increased by 2 to 4°C. And they involve, second, the development of contingency plans for a “4 degrees plus” world. Geoengineering can be part of those contingency plans under the condition that independent technology assessments deem geoengineering safe for deployment.


Dr. Sabrina B. Schulz is currently a Fellow with the Stiftung Neue Verantwortung in Berlin where she leads a research group on geoengineering.

[1] This definition was first coined by the Royal Society in its 2009 report “Geoengineering the Climate. Science, Governance and Uncertainty”. It was then adopted by the IPPC in 2011:

The views expressed are those of the author(s) alone. They do not necessarily reflect the views of the American Institute for Contemporary German Studies.