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Melting ice forms rivers across the Sermeq Kujalleq Glacier
© Patrick Robert/Corbis
11 February 2015 16:30

Reaction: Geoengineering is no substitute for cutting carbon emissions, conclude US researchers

Robert McSweeney


Robert McSweeney

11.02.2015 | 4:30pm
GeoengineeringReaction: Geoengineering is no substitute for cutting carbon emissions, conclude US researchers

On Tuesday, the US National Research Council  published two new reports on ‘climate interventions’, or what’s more commonly known as ‘geoengineering’.

Geoengineering is the deliberate large-scale intervention into the Earth’s climate system to try and limit the effects of human-caused global warming, and it can be divided into  two main areas. Removing carbon dioxide from the atmosphere, sometimes known as Carbon Dioxide Removal (CDR), is one approach. The other is reflecting some sunlight away from the Earth before it can be trapped by greenhouse gases, referred to as ‘albedo modification’ in the reports, but more commonly known as Solar Radiation Management (SRM).

The new reports are the result of an 18-month study into the potential impacts, benefits and costs of geoengineering. The study produces a set of recommendations, which call for more research and development, but also caution that sunlight-reflecting technologies “should not be deployed at this time”.

Geoengineering Summary Table

Overview of general differences between carbon dioxide removal approaches and albedo modification approaches. Source: US National Research Council ( 2015)

While the reports make clear that geoengineering is not a substitute for global action to reduce carbon emissions, it recognises that some action may be necessary to avoid the worst impacts of climate change.

The reports have prompted a flurry of reaction, particularly in the US. Here are some of the selected highlights.

‘We’ve failed to reduce carbon emissions’

Geoengineering isn’t a new idea, says Bloomberg, pointing out that 50 years ago scientific advisors to President Lyndon Johnson issued a report discussing “the possibilities of deliberately bringing about countervailing climatic changes” to deal with rising carbon-dioxide levels.

The Guardian says the report brings a “once-fringe topic in climate science towards the mainstream”. While the Washington Post says having this debate shows that “we’ve failed to reduce carbon emissions enough to prevent the risk of dangerous climate change”.

Climate Progress highlights the way that geoengineering is described as “climate intervention”:

“[T]he reports are on ‘climate intervention’ because the Academy panel rejects the widely used term ‘geoengineering’. Why? Because ‘we felt “engineering” implied a level of control that is illusory,’ explained Dr. Marcia McNutt who led the report committee.”

‘Evil twin’

Much of the media concentrates on the two different methods of geoengineering, which the study covered in separate reports. National Geographic says there is a “good and a bad way to geoengineer the planet”.

So, which is good and which is bad? Ars Technica makes it clear: “If carbon removal is expensive, but relatively low-risk, albedo modification is its evil twin: cheap, but with tremendous risks.”

Scientific American points out that blocking the Sun’s rays doesn’t help with other impacts of rising levels of atmospheric carbon dioxide, such as “turning ocean waters more acidic or nights that get warmer and warmer under a thickening blanket of greenhouse gases”.

The Forum for Climate Engineering Assessment, based at American University in Washington DC, is concerned the reports are suggesting technologies to remove carbon dioxide could also tackle the root causes of climate change:

“Climate change is not solely a carbon dioxide problem. It is, rather, a fossil fuel combustion problem, meaning it is an energy system problem. The idea that carbon dioxide removal addresses the causes of climate change muddies the wider message that climate engineering is no real substitute for mitigation.”

Emphasis on research

The US Environmental Defense Fund says the reports represent a “significant milestone in public exploration of geoengineering issues”, and is an important input for fostering “wider dialogue”.

In the Dot Earth blog from the New York Times, Andrew Revkin says that the reports bring no great surprises, but they do provide a “great guide to both the scientific and societal issues”, such as how different nations could make collective decisions.

In The Guardian, Jack Stilgoe, who will shortly be publishing a book on geoengineering, says that the reports have much to recommend them, but are limited by focusing on scientific questions and answers:

“Geoengineering and research into it is not just about winners and losers, risks and benefits. It is not just a set of empirical questions. It is a profound social experiment.”

The New York Times interviewed one of the reports’ reviewers, Dr David Keith from Harvard University, who was pleased with the emphasis on research and development:

“I think it’s terrific that they made a stronger call than I expected for research, including field research.”

‘Wildly, howlingly barking mad’

Not everyone is happy with some of the reports’ recommendations. The US arm of Friends of the Earth says that it’s not possible to experiment with geoengineering:

“In order to have any noticeable impact on the climate or global temperatures, geoengineering projects must be deployed on a massive, global scale. Experiments or field trials equate to real-world deployment.”

The campaign group says the side effects of geoengineering could easily have “unintended consequences due to mechanical failure, human error, inadequate understanding of ecosystems and biodiversity and the Earth’s climate, unforeseen natural phenomena, irreversibility, or funding interruptions.”

Even one of the reports’ authors is still unimpressed by geoengineering. Prof Raymond Pierrehumbert, from the University of Chicago, explains why he still thinks it’s “wildly, howlingly barking mad” on

“Engineering is something you do to a system you understand very well, where you can try out new techniques thoroughly at a small scale before staking peoples’ lives on them. Hacking the climate is different – we have only one planet to live on, and can’t afford any big mistakes.”

Grist says the disagreements over geoengineering between scientists “gives you some indication of how far away we are from making it practically and politically feasible”.

Perhaps Climate Progress sums up the findings of the reports best:

“[The] proposed climate intervention strategies are both safe and affordable. But the strategies that are safe are not affordable, and the strategies that are affordable are not safe.”

Main image: In summer, the melting of the ice caps is creating rivers called “bedieres”, which disappear under the glacier, creating spectacular wells called “grinders”.
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