Research furthers our understanding of the potential to tweak Earth’s climate using sulfur dioxide aerosols

In 2016, back before I moved to Freethoughtblogs, I wrote a blog post titled “Geoengineering is dangerous, irresponsible, and unavoidable“.  My basic conclusion was this:

It’s tempting to simply wave away geoengineering as a bad idea that we should bury and be done with. There are countless ways that it could go horribly wrong, especially when enacted by billionaires like Gates and his ilk, who have little to no understanding of the ecosystems with which they want to tamper. With the possible exception of planting more trees and creating more wild spaces (which would, without question, work), pretty much every proposal for geoengineering has the potential to have devastating side effects that could make life on Earth much more difficult.

There’s one compelling reason not to throw it away altogether. The reality is that we are already engaged in geoengineering, and there is no question that the path we’re currently on will end badly. Like it or not, humanity has become a force of nature. The size of our population and the scale of our technology mean that we exert a global influence of the chemical makeup of our planet’s oceans, atmosphere, land masses. Currently, we are engaged in the kind of geoengineering that Svante Arrhenius calculated was possible over a century ago – raising the planet’s temperature by increasing greenhouse gas concentrations.

For the sake of our own long-term survival, not to mention the rest of life on Earth, we need to come to terms with the fact that our species exerts a global influence, and we need to take deliberate control of that influence. We are already geoengineers, we’re just not taking responsibility for it. It’s past time to do more than simply work on reducing our fossil fuel use – we need to think about how we manage the surface of the planet we live on, and how we can manage it for the benefit of all life on Earth – ourselves included.

Because right now, we still seem to be pretending that we can just stop having a planetary impact, and with our population headed for 10 billion in just a couple decades, that is the one option that is no longer available to us.

I think that geoengineering still presents a great deal of danger, particularly if it’s left up to despots or oligarchs with little concern for human life and a massive, wealth-induced case of Dunning-Kruger syndrome, where they think their wealth means they know better than people who spent their lives studying an issue, rather than hoarding money.

Still, it’s good that research continues into the various ways to make our interference in the planet’s climate deliberate and constructive.

The team found that halving warming by adding aerosols to the stratosphere could moderate important climate hazards in almost all regions. They saw an exacerbation of the effects of climate change in only a very small fraction of land areas.

Lead author, Professor Peter Irvine (UCL Earth Sciences), said: “Most studies focus on a scenario where solar geoengineering offsets all future warming. While this reduces overall climate change substantially, we show that in these simulations, it goes too far in some respects leading to about 9% of the land area experiencing greater climate change, i.e. seeing the effects of climate change exacerbated.

“However, if instead only half the warming is offset, then we find that stratospheric aerosol geoengineering could still reduce climate change overall but would only exacerbate change over 1.3% of the land area.”

The team emphasise that solar geoengineering only treats the symptoms of climate change and not the underlying cause, which is the build-up of CO2 and other greenhouse gases in the atmosphere. It should therefore be considered as a complementary approach to emissions cuts as a way to address climate change.


“Our results suggest that when used at the right dose and alongside reductions in greenhouse gas emissions, stratospheric aerosol geoengineering could be useful for managing the impacts of climate change. However, there are still many uncertainties about the potential effects of stratospheric aerosol geoengineering and more research is needed to know if this idea is truly viable,” added Dr Irvine.


The team are now researching the projected effects of stratospheric aerosol geoengineering on the water cycle in more depth to try to understand the potential benefits and risks to society and ecosystems.

I’m not a fan of the sulfate aerosol approach. There seems to be potential for real ecological damage from increased acidity in precipitation, particularly if it’s hitting ecosystems already weakened by the effects of a warming planet. There’s also the worry that the temporary cooling from the aerosol spray could slow efforts to adapt to climate change, and to transition to non-fossil energy sources. A reminder – if greenhouse gas levels continue to rise while the sulfate effect is keeping temperatures down, then as the aerosols precipitate out of the atmosphere, the planet will start warming faster, because there will be more insulation to trap heat. If we haven’t already massively changed how we respond to crises and to science, we could do more damage with this approach than if we did nothing at all. The proper place for something like sulfate aerosol distribution is after changes have already been made to our economic and political systems, and the work to seriously address climate change is already underway.

Doing this research is good, but it’s essential that we address the political/sociological elements of the problem.

Otherwise we won’t be solving the problem, we’ll be entering into a version of the Futurama “giant ice cube” approach, but with sulfur instead of ice. That’s not a road we want to go down.


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