High-Profile Geoengineering Experiment Shuts Down

A beleaguered solar geoengineering project failed to conduct field tests because of opposition from environmentalists and Indigenous residents

Harvard University ended a solar geoengineering research project after years of setbacks derailed efforts to infuse small parts of the sky with sunlight-blocking aerosols.

The principal investigator, Harvard researcher Frank Keutsch, is “no longer pursuing the experiment,” the university announced Monday.

Known as SCoPEx, short for “stratospheric controlled perturbation experiment,” the project focused on a form of geoengineering often referred to by scientists as solar radiation modification. The idea — largely hypothetical for now — is that humans can artificially lower the Earth’s temperatures by spraying reflective materials, such as sulfates, into the atmosphere. These reflective aerosols could then beam sunlight back out to space, cooling the planet and combating the effects of climate change.

It’s a contentious idea. Proponents of solar geoengineering research argue that scientists should explore all possible avenues to address the planet’s rapidly rising temperatures. But scientists caution that solar geoengineering could carry a wide array of unintended side effects, including negative impacts on the Earth’s ozone layer or weather patterns.