Engineering the Earth's atmosphere

Engineering students test effectiveness of geoengineering aerosols in the upper atmosphere.

Kyla Stocks - 21 August 2018

(Edmonton) Solar Geoengineering isn't a new concept, but a group of University of Alberta engineering students are the very first to test a method of reducing global warming proposed by Harvard University.

Sometime between Aug. 20 - 25 (weather permitting) in Timmins, ON, the University of Alberta Space Design Group (UASDG) will launch a payload of calcium carbonate (calcite) aerosols into the atmosphere with the help of a Canadian Space Agency stratospheric balloon.

In solar engineering, these microscopic particles of calcite act as tiny "mirrors" that reflect light from the sun back into space. The students are testing the effect of the particles with the ozone layer.

"We have a sample of calcite inside a reaction chamber, which goes up in with the balloon. The reaction takes place inside the chamber - we don't actually inject calcite into the atmosphere itself," explained Rahul Ravin (Mechanical '18), who founded the UASDG student group.

"The payload contains a valve that allows air to flow in. By looking for reaction products - in this case, salt - we can tell if a reaction took place."

The evidence of a reaction indicates whether the calcite aerosol is safe for the environment. This is only one of many considerations that take place when proposing this type of solution to global warming.

This test is based on a Harvard study created by a computer model which predicted that calcite would promote ozone production. To their knowledge, this study hasn't been practically tested with calcite before.

"For several decades, geoengineering has been in the research phase without much practical application," said Ravin. "By testing these theories, it moves the research forward towards commercial applications."

Ravin says that the student group is leaving the study of measurement of the effectiveness of these aerosols to disperse solar radiation to other researchers who specialize in the field of geoengineering.

"Of course, we're aware of policy and ethical implications of such a proposal," adds Ravin. "If you disperse something and it blows away, who is responsible? What are the air pollution implications?"

Funding for this stratosphere balloon project came from the Department of Mechanical Engineering, the Faculty of Engineering, the Shell Enhanced Learning Fund and a variety of other sources.

Now that he is graduated, Ravin is passing the torch to a new group of undergraduate students to propose a new project for next year.

"I'm proud of what I've accomplished with this group," said Ravin. "I hope more students will take this opportunity to get involved in space-related projects and geoengineering."