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Mat Hope

Mat Hope

19.12.2013 | 9:30am
GeoengineeringGeoengineering’s limitations: technical, social, and ethical
GEOENGINEERING | December 19. 2013. 9:30
Geoengineering’s limitations: technical, social, and ethical

As politicians edge towards agreeing a new international climate deal in 2015, policymakers are increasingly considering a broad sweep of policy options to reduce global greenhouse gas emissions – including techniques to deliberately ‘engineer’ the climate.

In a special edition of the journal Climatic Change, researchers have turned their attention to addressing some fundamental issues surrounding the future of geoengineering.

What is ‘geoengineering’?

The journal broadly defines two types of geoengineering: carbon drawdown and removal (CDR) and solar radiation management (SRM). In theory, both techniques could help address some, but not all, of the impacts of climate change.

CDR involves drawing greenhouse gas emissions out of the atmosphere and locking them away. For example, carbon capture and storage (CCS) technology – which can be fitted to power plants to reduce their emissisons – is a type of CDR. SRM techniques are a bit different. They involve reflecting sunlight away from the earth’s surface in various ways in an attempt to control the amount of warming that occurs, without actually affecting emissions. This can be done by creating clouds or putting mirrors in space to reflect sunlight, for instance.

This video has a lot more detail, but it’s nine minutes long, so perhaps grab a cup of tea before clicking:

The Solar Radiation Management Governance Initiative from Environmental Defense Fund on Vimeo.

Learning more

Geoengineering raises some tricky issues, which the academics try to address. One key question is whether geoengineering techniques could do enough to reduce climate impacts on their own, or if they need to be part of wider efforts to address climate change.

Three papers try to establish under what circumstances ways of changing the amount of the sun’s light that hits earth would be most useful.

Two academics from the Pacific Northwest National Laboratory, Steven Smith and Phillip Rasch, argue SRM is geoengineering is most useful if the planet turns out to be very sensitive to carbon dioxide emissions.

They argue that if climate sensitivity is high, SRM techniques become more valuable as an extra way to deal with large amounts of warming. If climate sensitivity turns out to be low, however, they say  “SRM would not be needed”.

That’s because temperature rise is only one of the climatic impacts of increased greenhouse gas emissions. Because SRM doesn’t remove carbon dioxide from the atmosphere, it doesn’t address climate impacts like ocean acidification, meaning other policies will need to be pursued alongside SRM. These would be sufficient to address climate change impacts if climate sensitivity is low, the authors argue.

There are other downsides to relying on SRM, according to two Netherlands-based scientists, Detlef van Vuuren and Elke Stehfest. If SRM became central to the world’s climate change mitigiation efforts but had to be halted quickly, there could be extreme temperature shifts as a consequence, they say. As such, their research suggests SRM is best deployed in combination with other policies, as “the risks of stopping its application seem severe”.


Despite the risks and technical challenges, it’s clear geoengineering techniques could – theoretically, at least – play a role in future climate change mitigation efforts.

But could the world work out how to do it cooperatively? A group of academics have drawn up five principles which they argue should guide geoengineering decisions, which they call the ‘Oxford principles’:

  1. Geoengineering should be in the public interest, and regulated to ensure this.
  2. The public should be involved in deciding whether geoengineering goes ahead or not – particularly people potentially affected by the technology.
  3. Geoengineering research should be transparent, with results published and made available to the public.
  4. Independent researchers not involved in the geoengineering projects should assess the potential impact of schemes.
  5. Governance structures should be in place before geoengineering schemes are rolled out.

The scientists hope the principles will help policymakers as they set about creating institutions to regulate geoengineering. But deciding how such institutions work is also tricky.

Two researchers from the University of Colorado, Lisa Dilling and Rachel Hauser, suggest setting up national geoengineering organisations which ultimately fall under the umbrella of a single, international organisation – similar to the International Council for Science (ICSU) or the World Meteorological Organisation (WMO). That way, international rules could be rolled out across countries, and enforced by a central body.

Ethical implications

It’s not just the practicalities of regulating geoengineering that need further thought, there’s also an ethical aspect to consider. After all, who has the authority to say whether or not people should actively manipulate the natural environment?

This consideration needs to be at the core of geoengineering decisions, says Dale Jamieson, a philosophy Professor at New York University. Working out who has the right to declare that geoengineering is needed is a tricky question, Jamieson argues, because “one person’s emergency is another person’s bad day at the office”.

Just as fundamentally, how do we decide whether or not geoengineering is “in the public interest”, as the first Oxford principle says it must be?

Stephen Gardiner, a philosophy Professor at the University of Washington, says geoengineering is not a straight-forward ‘public good’ as it’s not always clear who it will benefit, or how. He says “There is nothing magical about technological interventions in the Earth’s basic systems that implies (let alone guarantees) universal benefit”. There is simply too much uncertainty around geoengineering’s impacts for such a sweeping statement to be assumed to be true, he says.

That’s why it’s so important to include the public in the early stages of geoengineering debates, another group of academics led by University of Montana PhD researcher, Wylie Carr, argue. Carr’s team say “the time is right” for the public to be engaged on geoengineering issues precisely because large scale schemes currently seem a long way off.

Ahead of the game

While it’s unlikely the skies will be filled with balloons spraying artificial clouds any time soon, technology is being developed which allows humans to deliberately manipulate the environment.

With such power comes a responsibility to think about what the technical, political, and ethical implications might be. And these academics think that’s a job best done right at the outset.

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