Widespread use of technology that dims natural sunlight to help fight climate change should only be used as a last resort, scientists have warned.

Large scale use of the process — known as solar geoengineering — is a “terrifying” concept that is only likely to be used in the future if significant regions of the planet become too warm to be habitable, Harvard University Professor Frank Keutsch told The Times.

Despite the concern, Keutsch is leading a project to study such technology, which could start later this year.

In theory, solar geoengineering is based on the idea that experts can reduce the impact of global warming by reflecting sunlight back into space using chemicals.

In the case of Keutsch’s experiment, the chemical will be calcium carbonate, which is essentially a chalk dust. If the plan is green-lit, a high-altitude balloon would disperse the mineral dust to study the viability, and risks, of solar geoengineering.

The process is not without controversy, as some experts have voiced fears that blasting chemicals into our immediate orbit tampers with the natural order, making weather less predictable or threatening populations’ food supplies by causing drought.

For now, research into the field is fairly limited. That’s what the Harvard project, called the Stratospheric Controlled Perturbation Experiment, or SCoPEx, aims to fix.

The SCoPEx project is partially funded by the Harvard University Solar Geoengineering Research Program (SGRP), which lists Bill Gates as one of its philanthropic donors.

According to Snopes, SCoPEx is also financed by the Fund for Innovative Climate and Energy Research (FICER), a fund for research grants co-created by Gates in 2007.

David Keith, a Harvard University professor also spearheading the SCoPEx project, said solar geoengineering will likely complement other carbon reduction methods, but noted it will be future generations that will ultimately have to live with the potential consequences.

He told The Times: “The decision we face now is whether to study it seriously … Doing serious investigation of what its risks are and how well it could work provides the next generation with better information to make a more informed decision.

“It doesn’t guarantee they’ll make the right decision. But in my view we have a duty to provide them with that information, so they can make those decisions in the face of really horrific climate risks.”

A review is ongoing to determine if the proposed balloon launch alongside the Swedish Space Corporation (SSC) can go ahead. If given the go-ahead, the experiment could take place in June, 2021, from the Esrange Space Center in Kiruna, Sweden.

The first takeoff would not release aerosols into the skies, however. Instead, the balloon would test properties of the hardware and software needed for future trials, including propellers, power, data, navigation and the communication systems.

The ultimate aim is not to roll out some major solar geoengineering apparatus, but to collect data that will better inform computer models, researchers said.

An FAQ published on the SCoPEx site says: “This knowledge will improve large-scale models that will in turn improve estimates of the overall efficacy and risks of solar geoengineering. This may seem like an idle distinction, but it matters.

“We are not, for example, testing whether it’s possible to scatter sunlight back to space, because there is no meaningful scientific uncertainty about that question.”

According to the team, the design for future SCoPEx flights required a balloon that can fly a 600 kg payload close to an altitude of 12 miles. In the future, a small amount of the dust — between 100g to 2kg — would be released to study atmospheric changes.

The chemical is non-toxic and the amount released will also be small. In fact, it would be less material than spews from airplanes, rockets or routine balloon launches.

Keith wrote in a blog post last December there are “no easy answers” to climate change and noted that a “technology’s risks depend on how it’s used.”

He wrote: “The obvious nightmare is that the future possibility of geoengineering slows efforts to stop emissions but that the technology turns out to be infeasible.”

Explaining the balancing act, he continued: “People are right to fear over-reliance on technofixes. But there’s another nightmare: It’s that after bringing emissions to zero, we realize in hindsight that early use of geoengineering could have saved millions of lives lost in heat waves and helped preserve some of the natural world.”

Ultimately, Keith said that more study was needed, writing: “It would be crazy to start deploying solar geoengineering today. It’s perhaps equally crazy to keep ignoring it.”

Source: Jason Murdock, Newsweek