NASA’s James Hansen has few peers when it comes to the title of leading climatologist-turned-policy-wonk, but Mike Hulme of the University of East Anglia (yes, that university) is giving him a run for his money. Hulme’s latest entry is a cautionary tale involving the challenges involved in geoengineering.
In Yale e360, Hulme argues that the technical obstacles to making the Earth’s climate do what we want aside, the politics of trying to change the radiative heat balance of the atmosphere are problematic in the extreme.
Who, he asks,
is entitled to initiate the large-scale deployment of a climate intervention technology — and under what circumstances?
Just as Hansen did in his book Storms of My Grandchildren, Hulme indulges in a little science fiction to illustrate what might lie ahead if we start injecting sulphate aerosols in the air in hopes of reflecting more of the sun’s rays before they reach the surface:
It is January 2028 and the United Kingdom — one of the permanent members of the UN Security Council — puts forward a formal resolution to start the systematic injection of sulfate aerosols into the stratosphere. The UK’s argument is that with Arctic sea ice extent the previous summer having shrunk to just 25 percent of its late-20th century value, with monitors in Canadian permafrost identifying increased rates of methane release, and with the explosion at a nuclear reactor in China two years earlier leading to a moratorium on all new nuclear power plant construction, such direct climate remediation measures are called for.
The Intergovernmental Panel on Climate Change (IPCC) provides a report for the Security Council on the regional climatic risks of such intervention. Based on the best Earth system models, the IPCC offers probabilistic predictions of the 10-year mean changes in regional rainfall around the world that would result from sustained aerosol injection.
Over the following months, protesters attempt to sabotage some of the planes being used to inject aerosols, and direct-action groups affiliated with HOME (Hands Off Mother Earth) send up their own aircraft in symbolic efforts to scrub the aerosols from the stratosphere. After one year the deployment is temporarily halted and climate data are evaluated.
Global temperature has indeed fallen from the previous 10-year mean of 15.23º C (the 1961-1990 average was 14º C) to just 14.57º C, the coolest year on the planet since 2014. But regional climate anomalies have been large and variable. Of most concern was a failure of the Asian monsoon, at the cost of $50 billion to the Indian economy, and the most intense cyclone season in the South China Sea for 20 years.
That’s not the end of the story. (Something about a pair of renegade Canadian billionaires?) It is just the start.
Hulme is not the only one pointing out that crafting an international consensus on geoengineering will probably make the quest for a global climate change treaty look like child’s play. Writing recently in New Scientist, Jim Giles suggests that
… global negotiations could become impossible to manage, and [others] cited UN-led climate talks as an example of how all-inclusive efforts can fail to solve problems requiring decisive action.
One can make a compelling argument that if we fail to reduce fossil-fuel emissions significantly in the next three decades or so, we won’t have a choice but to start tinkering with planetary albedo or finding some way to suck greenhouse gases from the air. But strategies focused on the former will not stop ocean acidification, which would lead to a collapse of the marine food web and massive starvation. The latter would be prohibitively expensive, both in economic and, more importantly, energy costs.
To me, it seems foolish to rely on our technical and diplomatic ingenuity to save civilization from the perils of an overheated planet. Better to keep kicking the can of emissions reductions.