Can We Afford To Use Solar Geoengineering To Curb Global Warming? New Study Weighs In


Dr. Alfredo Carpineti

Senior Staff Writer & Space Correspondent

clockNov 23 2018, 16:13 UTC

The Moon through the Stratosphere. NASA

The climate change clock is ticking faster than ever and with politicians stalling, analyses and re-analyses of new and old solutions are constantly being brought forward. One that has never gone out of style is the potential use of sulfur particles in the higher atmosphere to curb the effects of global warming. A new study, published in Environmental Research Letters, focuses on three main questions. Is it possible? Is it affordable? And can you do it in secret?

Before we get to the answers, it is important to know that the idea, known as stratospheric aerosol injection (SAI), comes from a natural event. In 1815, Mount Tambora in Indonesia erupted releasing 100 cubic kilometers (24 cubic miles) of material. It was the biggest eruption in 1,300 years and the aerosol in the atmosphere led to a short global cooling. 1816 was known as the year without summer.


But natural doesn’t mean good. The volcanic winter led to widespread famine and deaths (but also Frankenstein so, you know, there’s some positives). Researchers have created models showing that such an intervention would be deadly for many species worldwide. And sulfur only stays in the atmosphere for a short while compared to the hundreds of years that CO2 can persist.

The new study doesn’t focus on if we should do it. It looks at our capabilities for doing it. The researchers investigate an SAI plan to launch a fleet of stratospheric planes to deliver the sulfur over a time scale of 15 years.

"Solar geoengineering is often described as 'fast, cheap, and imperfect’,” co-author Dr Gernot Wagner, from Harvard University, said in a statement. "While we don't make any judgment about the desirability of SAI, we do show that a hypothetical deployment program starting 15 years from now, while both highly uncertain and ambitious, would be technically possible strictly from an engineering perspective. It would also be remarkably inexpensive, at an average of around $2 to 2.5 billion per year over the first 15 years."


This enterprise would require modified airplanes that can get to the stratosphere. They would need to have the same capacity as jetliners but with double the wingspan and thrust. The team expects 4,000 trips to happen in the first year with a fleet of eight planes. This would then expand to over 60,000 flights from a fleet of almost 100.

Neither the cost nor tech is particularly inaccessible. So the researchers wondered if this might be developed and deployed in secret. Given the number of flights required to make it work, no organization or “rogue nation” would be able to do it without notice. But it would be a great action movie. Small country tries to avert global catastrophe with science plan of dubious success, starring Janelle Monae. I’d watch that.

  • tag
  • global warming,

  • stratosphere,

  • solar geoengineering