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Solar Radiation Management

The first global conference on climate change took place in 1988, in Toronto. Now, 20 years later, scientists and diplomats are still meeting about the issue, and apart from the Paris Climate Accord signed two years ago, not much has changed. We’ve been manipulating Earth’s climate for more than 100 years. Now we have the option to do it intentionally. At the time of the Paris Accord, the Earth’s surface temperature was 1.98˚ F above the late 19th century average, and emissions had plateaued. Now, they’re on the rise again. That has some scientists thinking that cutting emissions may not be enough—we may have to resort to more drastic measures. 

Carbon dioxide removal technologies like BECCS, which removes carbon dioxide from the atmosphere using plants as the collectors, are helpful—but may not be potent enough. A more controversial form of what scientists are calling geoengineering is called solar radiation management. This involves reflecting heat away from the Earth instead of siphoning it out of the atmosphere. 

The strategy takes its cue from volcanoes, which noticeably lower the Earth’s average temperature by spewing sulfur particles into the stratosphere. The anthropogenic version involves spraying sulfate aerosols into the sky via a plane. 

It sounds like science fiction, but to many scientists, it’s a crude approach. “That’s a pretty unsophisticated way to cool the planet,” said Jane Long, a former associate director at Lawrence Livermore National Laboratory and now senior contributing scientist for the Environmental Defense Fund.

A new study published in the journal Nature this week attempts to predict what would happen if geoengineers added 5 million tons of sulfur dioxide to the stratosphere every year for 50 years—and then abruptly stopped (if, perhaps, funding ran out or the system was sabotaged). The consequences of “sudden termination” would be scary, according to the researchers. Earth would warm so quickly that animals wouldn’t have time to catch up; they’d be migrating up to 30 to 60 miles a year in order to reach more comfortable terrain—for nearly all of them, that’s nearly impossible. 

“Organisms cannot in any reasonable way keep up with these changes,” said Jessica Gurevitch, one of the paper’s authors and a professor of ecology and evolution at Stony Brook University. The result could throw entire ecosystems—and the planet’s biodiversity at large—into a state of chaos. 

The resulting climate situation could be two to four times worse than if we didn’t do anything at all.

“One of the issues with solar radiation management has always been that if you stop suddenly, the Earth immediately ramps up to what it would have been without it—so there’s rapid warming,” Long said. 

“If you don’t mitigate [by reducing emissions], you’re going farther and farther from the known state of climate, which is really dangerous.” 

Long emphasizes the importance of planning and regulation if we’re going to seriously consider geoengineering. These projects are also hugely controversial (this iron-dumping ocean experiment sparked some outrage last year), so efforts to control implementation and public understanding are key.

“We don’t [yet] know how to govern the deployment of this technology,” she said. “As we start research, it’s very to critical to start implementing a muscle of governance.”

As an ecologist, Gurevitch has a different perspective on all of this. She thinks the results are critical, but perhaps more interesting is the interdisciplinary nature of this work—which brought together climate science, biology, ecology, atmospheric science, and more.

“The real value is this creative element in science where different scientists can get together and come up with an entirely new perspective than they would have come up with on their own,” Gurevitch said. “That’s one of the ways science progresses and can lead to a different way of seeing things.”

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