Will geo engineering pave the way for reducing CO2 emissions?

Imagine looking up in the sky. There, many miles above your head, you see what looks like a gigantic mirror. It is actually an enormous solar shield launched to reflect sunlight and reduce the amount of solar energy heating the earth. It is part of a last ditch effort to save us from total environmental catastrophe. It is geoengineering.

Geoengineering is an umbrella term for large-scale interventions to counteract anthropogenic (human caused) climate change. These efforts can be divided into two broad categories: those aimed at carbon dioxide capture from the atmosphere and subsequent long term storage, and those aimed at counteracting the effects of global warming through solar radiation management (SRM).

The main difference between these two types is that the first aims to reduce the concentration of CO2 in the atmosphere, thus making it more likely that our emissions not will exceed 350 ppm (parts per million), often quoted as the ‘target’ ratio for carbon dioxide molecules in order to prevent significant climate change. Those aimed at limiting the amount of solar energy on the other hand, are aimed at reducing the direct heating of the globe. They do not address the problem of increased amounts of carbon gasses in the atmosphere.

Space reflectors are just one of a wide range of geoengineering proposals. For CO2 reduction, suggestions include Ocean fertilization or nourishment: sprinkling iron on oceans to stimulate the growth of certain types of plankton. These small organisms feed on CO2 and live near the surface of water where there is sufficient light to support photosynthesis. Afforestation on a very large scale, would enable the removal of CO2 until the trees were cut down or decomposed. CO2-capture from the air would involve building huge processing towers that suck in air and using sodium hydroxide, remove the CO2 as the air passes through the tower.

Solar radiation projects include stratospheric aerosols: dispersed into the stratosphere, these aerosols are designed to reflect sunlight and increase cloud condensation. Sun reflectors in deserts would involve large desert surfaces being covered with sun-reflecting sheets. The basic idea is the same as for space reflectors – to reflect sunlight and thereby slow down the heating of the globe.

‘If geoengineering is to play a key role in the future, it needs to be scaled up raising numerous questions related to technological readiness, costs, safety and possible side effects.’

Ongoing afforestation can be considered as an example of existing geoengineering but is currently on a small scale. If geoengineering is to play a key role in the future, it needs to be scaled up raising numerous questions related to technological readiness, costs, safety and possible side effects.
Some geoengineering technologies are ‘readier’ than others. Injecting sulfur into the stratosphere will probably not be technologically difficult neither will afforestation. But building reflectors large enough to reflect significant amounts of solar energy presents an enormous technological challenge. Air capture with CO2 removal? Will we be able to store the necessary amounts of CO2?

Costs and side effects

The costs and financing of geoengineering projects will obviously be a major issue but also the side effects of intervention. For example, ocean fertilization could lead to nutrient depletion. As the plankton grow, they will not only eat the CO2, as intended, but also other nutrients that other organisms eat. Another example of side effects is that spreading aerosols into the atmosphere is can reduce rainfall in the tropics. The particles that are meant to absorb heat from the sun may also absorb some of the heat energy that comes from the surface of the planet. This heat plays an important role in the production of tropical rainfall, with a danger of causing significant harm to some of the most important ecosystems of the globe. The key point is that geoengineering will come at significant cost, and side effects will be difficult – if not impossible – to predict.

Is Geoengineering a Case for TA?

Yes. With a mission of providing advice to policy makers on pressing policy issues, TA can foster critical reflection on which of these (if any) technologies should be developed and how the benefits should be weighed against possible side effects. And not least, TA can stimulate public debate as a means for the democratization about technological choices.

Several TA institutes have done studies on geoengineering:

In 2009, the UK Parliamentary Office on Science and Technology (POST) published Geo-Engineering Research, which summarized the arguments related to research funding. It suggested: “A relatively modest research programme, with a UK contribution of £10-20M could advance relevant knowledge significantly.” Climate engineering research programmes are currently ongoing at several universities in the UK.

The Rathenau Instituut is conducting research into various forms of climate engineering and in 2013 published a policy brief entitled Climate engineering: hype, hope or despair? One of their recommendations was to put Carbon Dioxide Removal technology on the agenda of the climate negotiations in 2015 in order to include regulations in the Climate Agreement.

The Office of Technology Assessment at the German Bundestag Büro für Technikfolgen-Abschätzung beim Deutschen Bundestag (TAB) is currently working on a comprehensive overview (2011-2014) of the current state of knowledge with regard to technological and natural scientific aspects of the different geoengineering concepts proposed and exploring the facets of these concepts in terms of (international) law, ethics, socio-economics and politics. “Science has only just started to deal with these and other questions so that there is still a considerable lack of knowledge.”

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Rathenau Instituut
GAO (Government Accountability Office, USA)


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