Climate intervention techniques such as carbon dioxide removal and technologies that prevent sunlight from reaching Earth’s surface are not a replacement for reducing carbon emissions, found a National Research Council committee.
In a two-volume evaluation of proposed climate-intervention techniques, the National Research Council concluded that there is no substitute for dramatic reductions in greenhouse gas emissions to mitigate the negative consequences of climate change.
It also stressed that carbon dioxide removal and albedo-modification techniques, which aim to increase Earth’s ability to reflect incoming sunlight, are more accurately described as ‘carbon intervention’ strategies; the more commonly used term ‘geo-engineering’ gives the false impression of precise control over the climate.
The committee concluded that many strategies to remove carbon dioxide from the atmosphere have limited technical capacity and large-scale deployment would cost as much or even more than replacing fossil fuels with low carbon-emission energy sources, the committee said.
The report was especially critical of two such techniques – using enhanced weathering processes on land and in the ocean to accelerate natural removal of carbon dioxide from the atmosphere or ocean iron fertilisation – because of their high environmental and socio-political risks.
The committee was particularly adamant that albedo-modification technologies should not be used at this time, warning that they would only temporarily mask the warming effect caused by high CO2 concentrations, while presenting serious known and possible unknown environmental, social, and political risks, including the possibility of being deployed unilaterally.
Calling reduction emissions “the most effective, least risky way to combat climate change”, the committee concluded that if society decides to intervene in Earth’s climate, the actions should be informed by a far more substantive body of scientific research than presently exists, including ethical and social dimensions.
The National Research Council is the principal operating arm of the National Academy of Sciences and the National Academy of Engineering.