Unconscious Interventions
Bryony Worthington talks with Kelly Wanser about the need for more research into climate cooling, and why we might need it in our climate arsenal.
As climate impacts mount, pressure will build on policymakers to find ways to alleviate the crisis. Public budgets will be stretched by adaptation needs and political instability seems almost certain to increase. In this context, geoengineering, or direct human intervention to cool the planet is likely to become more urgent.
Trying to cool the planet will never be a better bet than stopping burning things and reducing the size of the pollution blanket now engulfing us. But that transition is going slowly and there are still lots of things we don’t know about the sensitivity of the global climate system. In risk terms, the likelihood and the severity of impacts from a warmed world are still increasing, so our list of effective mitigating actions needs to be expanded.
Since the Paris Agreement was signed in 2015, emissions and concentrations of greenhouse gases have continued to increase. As a result, we've effectively lost two decades in the time we had to avoid passing dangerous temperature increases. (This EU Copernicus article from the end of 2023 is a good summary of how dire things are.)
While our economies are still largely powered by fossil fuels, we are unconsciously conducting two geoengineering experiments at once: increasing greenhouse gases, and simultaneously releasing large volumes of particulate matter and other pollutants as a co-product. Greenhouse gases have led to an increase in temperatures since the Industrial Revolution, but co-emitted aerosols, such as those produced by freight shipping or from burning coal, have likely been keeping temperatures lower than they would otherwise have been, by reflecting some of the sun’s rays away from Earth.
As we shift from coal and oil and increase our use of ‘cleaner’ fossil fuels, we are reducing aerosol pollution. This may, in the short-term, accelerate warming, as we scrub out reflective aerosols but continue burning fossil fuels. And as we switch to burning ‘natural gas’ or methane we have the problem of fugitive methane emissions which have a very high warming potential in the short term. Hydrogen (green or otherwise) escaping into the atmosphere can slow the breakdown of methane, again increasing atmospheric warming in the short term.
Given all this, how do we work out if we can safely and effectively implement large-scale climate cooling? And how will we know if and when it’s time to pull this ‘emergency rip cord’? These questions deserve answers, and we need those answers soon. Because if we cut emissions too late and fail to intervene, feedback mechanisms could push us over irreversible tipping points that make it impossible to retain a safe climate. We have spent centuries conducting unconscious experiments in geoengineering, so researching how to consciously and carefully do it seems a sensible precaution.
For my latest episode of Cleaning Up, I sat down with Kelly Wanser, Executive Director of the nonprofit SilverLining, which was set up to advance research into climate interventions. In particular, they support early-stage experiments to improve the reflectivity of clouds, potentially one of the most rapid and cost effective options to cool the climate, and with the fewest risks. Kelly says that in theory, by brightening clouds and increasing the Earth’s reflectivity by “1 or 2%, you could offset the warming from greenhouse gases.” But research efforts into even this form of intervention are often beset by controversy and opposition.
In April, SilverLining supported an experiment aboard the USS Hornet to study how to produce the kinds of particles that could be used to brighten clouds. The experiment was widely reported by papers including the New York Times, and involved spraying a fine mist of sea-salt crystals into the air to assess whether the reflectivity of marine clouds can be increased.
The project was ultimately shut down following public backlash, something that is common with experiments linked to climate interventions. “There was one that was shut down in the UK years ago at Oxford, there was one that was shut down in Sweden,” says Kelly. “And they get a reaction and an opposition and a response before they're able to generate the science and information that would help people understand what they do.”
This form of NIMBYism is only one of the many challenges that Kelly, Silver Lining, and the network of academics they work with, face. Getting countries to work together on governing this kind of research into, and deployment of, these interventions is a much bigger conundrum.
When I started working on climate change I took it as read that we had all the instruments and scientific research programmes we need to monitor how the atmosphere was changing, and how quickly. Over time I, like Kelly, grew to realise that this is far from the case.
Climate research is expensive and modelling is stupendously complicated. There are vast numbers of known unknowns and probably as many unknown unknowns. This situation has to change. More public money needs to be allocated to monitoring our atmosphere — and top-down prioritisation undertaken to focus on the most pressing gaps in our knowledge. And we will need a global governance system that oversees this in the public interest.
Blasting our way off into space to become a ‘multiplanetary’ species might be a nice idea, but if we add one planet while losing another — the one that we are perfectly adapted to and call home — how on earth can this be seen as progress?
To listen to the episode, find Cleaning Up on your podcast platform of choice, or watch the video on YouTube here.