Once deployed, geoengineering gives excuses to avoid reducing carbon emissions.
We need to be very wary before we deploy any effort to create a man-made chemical sunshade to deflect a harmful rise in global temperatures.
Veteran Reuters reporter Alister Doyle published an intriguing story on research into "solar geo-engineering," which would mimic big volcanic eruptions that can cool the Earth by masking the sun with a veil of ash.
That research is now dominated by rich nations and universities such as Harvard and Oxford. But there are some serious caveats we must consider before going too far down this path.
What happens if we turn the sunshade off?
With so much at risk from climate change, scientists in developing nations understandably argue they must be at the table as these technologies are explored for their benefits and costs (see commentary in Nature). This story from Reuters explores an initiative, the Solar Radiation Management Governance Initiative (SRMGI.org) that is facilitating developing nation engagement in assessing solar geoengineering.
Let's hope their deliberations encompass the existential threat these technologies pose: Once employed, they give excuses to avoid reducing carbon emissions. Yet once they are deployed, what happens if major societal disruptions bring them to a halt (for example, if financial collapse means there are no longer resources to pay for them)? The pent-up pressure of carbon emissions that were permitted to enter the atmosphere because of the promise of solar geoengineering will likely rapidly assert their impact on global temperatures. Any assessment of solar geoengineering must examine this endgame.
There are other obvious risks, most especially that solar geoengineering to lessen temperature increases does nothing to prevent further accumulation of carbon dioxide in the oceans and fresh water bodies, exacerbating acidification.
That's well-known. But there are undoubtedly many unknown unknowns that will put into play be playing with solar geoengineering.
Read the full Reuters report here.