A primary-of-its-kind geoengineering experiment is about to take its first step

Trapped inside an extended glass tube in a ground-floor lab at Harvard College is a miniature copy of the stratosphere.

After I visited Frank Keutsch within the fall of 2019, he walked me right down to the lab, the place the tube, wrapped in grey insulation, ran the size of a bench within the again nook. By filling it with the proper mixture of gases, at specific temperatures and pressures, Keutsch and his colleagues had simulated the situations some 20 kilometers above Earth’s floor.

In testing how varied chemical substances react on this rarefied air, the workforce hoped to conduct a crude take a look at of a controversial scheme often known as photo voltaic geoengineering, which goals to counter local weather change by spraying tiny particles into the stratosphere to mirror extra of the solar’s warmth again into area.

However is what’s in that tube “actually what the stratosphere is like?” asks Keutsch, a professor of engineering, chemistry, and atmospheric science, as he gestured towards it. “That’s the query. We attempt to consider every part, however I might argue you by no means fairly know.”

That’s why he and fellow researchers, together with Harvard local weather scientist David Keith, need to transfer their experiments out of their toy stratosphere and up into the actual one. They hope to conduct a collection of scientific balloon flights, the primary of which may launch from the Esrange Area Heart in Kiruna, Sweden, as quickly as this summer time.

I critically hope we’ll by no means get in a state of affairs the place this really must be executed, as a result of I nonetheless assume it is a very scary idea and one thing will go improper.

Frank Keutsch, principal investigator of SCoPEx

The preliminary flight will merely consider whether or not the plane’s gear and software program work correctly within the stratosphere, the place temperatures can plunge under 50 ˚C and the stress ranges from one tenth to 1 thousandth the quantity at sea degree. However in subsequent launches, the researchers hope to launch small quantities of the kinds of particles that would scatter daylight.

In a world that’s reducing carbon dioxide emissions too slowly to stop catastrophic local weather change, photo voltaic geoengineering may purchase a while. However doing it on a big scale may imply messing with planet-wide climate patterns. The consequences are unpredictable; in some locations, they could even be disastrous.

Within the coming weeks, due to this fact, an impartial advisory committee that’s reviewing the authorized, moral, and environmental points surrounding the mission is anticipated to find out whether or not the analysis group ought to proceed with the primary flight. The committee may also must rule earlier than any flights that truly launch supplies, and decide what steps the analysis workforce ought to or should take to have interaction with the general public and regulators.

If these launches are authorized—and that’s nonetheless a giant if—they would be the first geoengineering experiments within the stratosphere. However earlier than the balloons have even left the bottom, they’re already drawing criticism.

Too harmful to make use of

The concept of cooling the planet by dispersing particles within the ambiance, dimming daylight and offsetting a few of the warming pushed by greenhouse-gas emissions, has a precedent: nature already does it.

Main volcanic eruptions akin to Mount Pinatubo in 1991 have spewed hundreds of thousands of tons of sulfur dioxide into the air, miserable international temperatures within the years that adopted. The sulfur dioxide emitted from coal crops and ships produces measurable cooling results as nicely.

To some critics, doing this intentionally as a measure in opposition to local weather change is reckless even to ponder, not to mention experiment with. Some research have discovered that photo voltaic geoengineering may considerably alter rainfall patterns and reduce some crop yields in sure locations. Alternatively, different papers have concluded that the environmental negative effects might be small as long as geoengineering is finished in a reasonable manner.

However all of the analysis executed so far, with just a few small-scale exceptions, has been performed in pc fashions or lab experiments. So Keutsch and his colleagues argue that their balloon trials are a important subsequent step.

The essential concept for his or her so-called SCoPEx experiments, first proposed again in 2014, is to launch a balloon, geared up with propellers and sensors, that might launch as much as two kilograms of sub-micrometer-size particles in a roughly kilometer-long plume. A business airliner pumps out related quantities of fabric each minute, Keith notes.

Then the balloon would tack round and slowly zigzag via the plume from the wrong way. Its sensors would try and measure how broadly the particles disperse, how they work together with different compounds, and the way a lot daylight they mirror.


No matter they discovered might be fed again into pc fashions, refining our understanding of what spraying a whole lot of hundreds to hundreds of thousands of tons of fabric might do.

At this level, the workforce hopes to conduct a collection of flights over various years. At first, they intend to launch a fantastic mud of calcium carbonate—the principal ingredient of chalk—however ultimately the researchers need to take a look at different supplies, possible together with sulfuric acid (which is a by-product of the sulfur dioxide launched from volcanoes).

However some concern that even these restricted experiments are a step too far.

Wil Burns, co-director of the Institute for Carbon Elimination Regulation & Coverage at American College, believes there must be an try to achieve some form of international consensus about whether or not society ought to ever use such a software earlier than outside experiments go forward.

However for him, the reply is not any: The environmental impacts are unknown. The challenges of governing such a software are immense—a single nation may perform photo voltaic geoengineering by itself, however all nations can be affected. And future generations might be compelled to handle the results for a whole lot of years. He provides that we will’t know what it’ll actually do at a planetary scale till it’s totally deployed—and at level, we’ll be caught with any droughts or different risks till the results subside.

Some environmental teams and geoengineering critics are calling on authorities officers in Sweden, the place the primary SCoPEx flight would launch, and the heads of the Swedish Area Company, which might handle them, to oppose the experiments. They argue not that the analysis itself presents environmental dangers however that it creates a “slippery slope towards normalization and deployment” of a deadly and highly effective software.

Photo voltaic geoengineering “is a know-how with the potential for excessive penalties, and stands out as harmful, unpredictable, and unmanageable,” reads a letter issued by Greenpeace Sweden, Biofuelwatch, and different teams. “There isn’t any justification for testing and experimenting with know-how that appears to be too harmful to ever be used.”

The reluctant researcher

Keutsch says it’s a “very legitimate” concern that geoengineering experiments may make eventual use of the know-how extra possible. As he advised me throughout an interview in his workplace, he himself thinks geoengineering is the improper method to handle local weather change. He in contrast it to opiates that ease acute ache however result in different issues like dependancy. The far safer, simpler resolution can be to quickly slash greenhouse-gas emissions.

However, he fears, local weather change is to this point alongside and so more likely to turn into so disruptive that some determined nation might transfer forward with geoengineering anyway. An earlier Harvard examine discovered that the price of creating and flying a fleet of specialised planes to do the job would price as little as $2 billion a 12 months, placing it throughout the financial attain of many nations.

Because it’s the one software that would make any actual distinction to international temperatures throughout the interval of a political time period, it may turn into an extremely seductive choice in nations struggling via lethal warmth waves, droughts, famines, fires, or floods. Utilizing it with out adequate analysis can be “very harmful,” Keutsch says.

Harvard professor Frank Keutsch, principal investigator of SCoPEx.

“Folks assume that as a result of I’m doing geoengineering analysis I form of need to do geoengineering,” he says. “My view is definitely very strongly that I critically hope we’ll by no means get in a state of affairs the place this really must be executed, as a result of I nonetheless assume it is a very scary idea and one thing will go improper.”

“However on the similar time, I believe higher understanding what the dangers could also be is essential,” he provides. “And I believe for the direct analysis I’m most thinking about, if there’s a kind of fabric that may considerably scale back dangers, I do assume we must always find out about this.”


The workforce initially hoped to start balloon flights as early as 2018 in Tucson, Arizona, and subsequently explored plans in New Mexico. They opted to maneuver the primary effort to Sweden due to “COVID-19 and different logistical and scheduling challenges,” based on the mission web site.

A part of the delay was as a result of Keutsch workforce’s resolution to arrange an impartial committee to judge the moral and authorized impacts of their proposed experiments. They didn’t must have one, for the reason that analysis effort has no federal funding. (Certainly, when the mission started, there was no US federal funding for geoengineering analysis. The mission runs on inside Harvard cash and donations from people and teams together with Invoice Gates, the William and Flora Hewlett Basis, the Alfred P. Sloan Basis, and others.)

However Jane Lengthy, a former affiliate director at Lawrence Livermore Nationwide Laboratory, strongly advisable that an exterior evaluation committee be created. (She additionally helped decide its chairperson.) “It was necessary for the way forward for this know-how that they’re not seen as unhealthy scientists working off to do some experiment with none evaluation,” she says.

Lengthy stresses that the experiments, as first proposed, are very small scale and unlikely to current well being or environmental risks. However the board, she says, forces the researchers to articulate what the work is for and to handle public issues.

The committee has already issued a report offering solutions on how the analysis workforce ought to talk with the general public earlier than any flights that launch particles. Amongst different issues, it recommends making a briefing e-book to elucidate the problems and welcoming individuals who reside close to the balloons’ flight path to “take part in deliberative dialogue in regards to the experiment itself in addition to governance of photo voltaic geoengineering analysis.”

Nonetheless, Burns and others argue that the committee is lacking some essential voices, together with critics of geoengineering analysis and representatives from poorer nations. And he believes these blind spots are evident within the committee’s preliminary report. “It assumes, and form of evinces a bias, that we’re solely doing the general public engagement to determine the best way to get to the subsequent stage when it comes to subject experiments—and that appears to be making a form of foregone conclusion when it comes to what is going to occur and what ought to occur,” he says.

What they could study

Keutsch’s workforce has already run pc simulations exploring how the particles launched from their gear will dissipate into the air. If and after they beginning testing this for actual, they need to be capable of measure extra exactly how specks of calcium carbonate or sulfuric acid unfold out or clump collectively—an important take a look at of how nicely these supplies may work for geoengineering. If the particles are too huge, they’ll sink too rapidly out of the stratosphere, requiring extra supplies to scatter the identical quantity of daylight.

One other essential query is how the particles will react with different chemical substances within the stratosphere—significantly the calcium carbonate, because it doesn’t happen up there naturally.


The workforce selected calcium carbonate as a substitute of sulfates for 2 causes, Keutsch says: sulfates eat away on the protecting ozone layer, and whereas they’ve a cooling impact on the Earth’s floor, they heat the stratosphere. That might fire up climate patterns in ways in which might be arduous to foresee. “You are attempting to poke the Earth system in ways in which I don’t assume our fashions are good at predicting,” he says.

Calcium carbonate comes with its personal unknowns, nevertheless. These experiments within the glass tube discovered that it isn’t significantly reactive with the compounds it’ll encounter within the stratosphere. However the best way it interacts with different chemical substances in the actual one may have an effect on how a lot ultraviolet radiation is absorbed and the way a lot daylight is scattered.

The observations from the flights may assist refine our understanding of how a lot of those supplies could also be wanted to decrease international temperatures, what dangers releasing them may pose—or whether or not it’ll work in any respect.

However there’ll nonetheless be actual limits on what the researchers can study from tiny balloon experiments. They received’t be capable of detect the longer-term destiny of particles launched into the stratosphere, as a result of they’ll rapidly turn into too dilute to detect. Furthermore, Keutsch acknowledges, there are merely some issues that may’t be identified till somebody deploys photo voltaic geoengineering at full scale.

“The Earth system is so advanced,” he says. “I don’t assume we will predict completely. We will’t ever be actually positive of what’s going to occur if you do that.”

Related Posts

Leave a Reply

Your email address will not be published.