Overline: Intense Debate about Targeted Interventions in the Climate System
Headline: Climate Engineering

While there is still hope that risks from climate change can be limited by cutting greenhouse gas emissions, there is also a perception that ‘time is running out’. This perception of a looming watershed has given rise to calls for research on intentional, large-scale interventions into the climate system, referred to as either ‘climate engineering’ or ‘geoengineering’. Both terms describe a diverse and largely hypothetical array of methods for manipulating the global climate in order to moderate or forestall some of the numerous impacts of climate change.

Chancen und Risiken von Climate Engineering

So far, the success of efforts to reduce the emission of greenhouse gases has been limited. Moreover, international climate negotiations and the transformation of energy infrastructures towards sustainability remain slow-paced. Should current emission patterns continue, this will likely lead to substantial global warming, sea level rise, ocean acidification, and changes in the frequency, intensity and locations of weather extremes. Many societies will struggle to adapt to these changes. Targeted interventions in the climate system have the potential to allow a degree of control over global average temperatures.

Promises and risks of climate engineering

There are various approaches to intentionally intervening into the climate. These are commonly grouped according to whether they attempt to actively remove carbon dioxide and other greenhouse gases from the atmosphere or whether they attempt to reflect incoming sunlight away from Earth and back into space. Options for removing greenhouse gases from the atmosphere include large-scale afforestation, the enhancement of weathering processes, or the direct capture of greenhouse gases from ambient air for subsequent storage. Options for reflecting sunlight back into space include the injection of reflective aerosol particles into the stratosphere or the brightening of marine clouds through the injection of cloud condensation nuclei, such as sea salt.

However, current knowledge suggests that any potential benefits of such interventions would be accompanied by significant risks and uncertainties. Climate engineering techniques are therefore the subject of intense debate and controversy within academia and society at large, which goes beyond the limited consideration of whether we are technologically capable of controlling global average temperatures. Rather, climate engineering emerges from a complex set of interactions between societal and technological developments that needs to be taken into account. These interactions shape the emergence of climate engineering approaches onto political agendas. Understanding this reflexive relationship is crucial to producing comprehensive, relevant knowledge to support decision-making about climate engineering.

IASS research on climate engineering

Our interdisciplinary team brings together physicists and chemists, international lawyers, political scientists as well as representatives from the fields of geography, philosophy and psychology.

We are especially interested in the governance of climate engineering techniques, including field experimentation on such techniques. We also work on the use of computer models to understand the impacts of sunlight-reflection techniques, and on the societal perception and deeper ethical implications of the full range of climate engineering techniques. A key aspect of our work is the transdisciplinary interaction with stakeholders from civil society and the policy-making community, to improve the accuracy, relevance and impact of our work.

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