Scientists Delay First “Sun-Dimming” Experiment After Public Outcry

July 6, 2021 at 3:53 pm




Harvard scientists were supposed to send an aerosol-injecting balloon into the stratosphere this summer to test technology that could dim the sun and cool the earth.





Harvard University scientists had hoped to test-fly a balloon aircraft designed to inject chalky dust into the stratosphere this summer in hopes of partially blocking out the sun to combat global warming.

“It’s a small scale experiment that will inject about a kilogram of particles into the stratosphere to generate a plume a few kilometers in length that will have absolutely no physical impact on the ground,” says Harvard Engineering and Atmospheric Science Professor Frank Keutsch in a video.

The so-called Stratospheric Controlled Perturbation Experiment was scheduled to take place last month, but was cancelled due to public outcry.

Environmental groups argue geoengineering could have drastic effects on rain patterns, leading to wild shifts in weather, droughts and major food shortages.

An advisory board to the scientists has elected to undergo further public consultation in hopes of assuaging fears, pushing back the potential launch date until at least 2022.

The several-million dollar experiment – which was set to take place in Sweden – has been funded by private donors, including Microsoft co-founder Bill Gates.

It’s designed to mimic the effects of a volcano, which has the temporary effect of blocking out some of the sun’s light and heat with its plumes of volcanic sulfuric ash, but critics warn trying to outsmart nature is rife with risks.

In their first test, the Harvard scientists want to use calcium carbonate, instead of sulfates, which can lead to ozone loss. “But because calcium carbonate does not exist naturally in the stratosphere, models for its behavior are uncertain,” admits David Keith, a Harvard energy and climate scientist.

“Even if it doesn’t deplete ozone, calcium carbonate will react with other gases and particles in the stratosphere, changing its composition— and potentially seed clouds in the lower atmosphere that might cool or warm the planet,” Perdue University atmospheric chemist Daniel Cziczo, who is skeptical of the experiment tells Science Magazine.

Even with all the risks, proponents claim we can’t cut greenhouse gas emissions fast enough to avoid climate disaster, and that “dimming the sun may be our only choice.”

The first flight would not inject any particles. It would only be a dry run of the steerable balloon and instruments. If all goes well, the experiment would inject up to 2 kilograms of calcium carbonate into the stratosphere, which, Harvard points out, is about how many aerosols commercial airplanes emit every minute.