Scientists have issued a stark warning that we should start thinking about unproven geo-engineering solutions so they are ready if we need them to combat climate change in the future.
Technological interventions such as injecting aerosols into the upper atmosphere to reflect heat, or seeding clouds to increase their reflectivity have been raised as possible ways we could cool the planet if we can’t – or won’t – act to reduce greenhouse gases in time to prevent a catastrophe.
But the scientists have made their recommendations reluctantly, acknowledging that if we interfere directly with the planet’s systems, we have no real hope of knowing how the process could end. As The Guardian reports:
The scientists were so sceptical about geo-engineering that they dispensed with the term, opting for “climate intervention”. Engineering implied a measure of control the technologies do not have, the scientists said.
Some of the possible options to reflect sunlight are detailed in a report by scientists from the Committee on Geoengineering Climate, the Board on Atmospheric Sciences and Climate, the Ocean Studies Board, the Division on Earth and Life Studies and the US National Research Council.
“The message is that reducing carbon dioxide emissions is by far the preferable way of addressing the problem,” said Raymond Pierrehumbert, a University of Chicago climate scientist, who served on the committee writing the report. “Dimming the sun by increasing the earth’s reflectivity shouldn’t be viewed as a cheap substitute for reducing carbon dioxide emissions. It is a very poor and distant third, fourth, or even fifth choice. |It is way down on the list of things you want to do.”
But old “technology” might be the best bet to geo-engineer the planet, according to a new report by Oxford University researchers.
They say that there are two techniques – tried, true and safe – that we should be putting effort into immediately – planting more trees and improving the soil by burying a layer of dense charcoal.
But, as The Atlantic reports, the Oxford scientists are also at pains to stress that these so-called “Negative Emissions Technologies” or NETs should not be seen as a substitute to reducing greenhouse emissions.
“NETs should not be seen as a deus ex machina that will ‘save the day,’” its authors wrote. NETs should instead be seen as one of several tools to meet the international goal of avoiding climate change greater than 2 degrees Celsius. Another crucial tool is reducing emissions.
Bill Condie is a science journalist based in Adelaide, Australia.
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