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



Trapped inside a long glass tube in a ground-floor lab at Harvard University is a miniature copy of the stratosphere.

When I visited Frank Keutsch in the fall of 2019, he walked me down to the lab, where the tube, wrapped in gray insulation, ran the length of a bench in the back corner. By filling it with the right combination of gases, at particular temperatures and pressures, Keutsch and his colleagues had simulated the conditions some 20 kilometers above the Earth’s surface.

In testing how various chemicals react in this rarefied air, the team hoped to conduct a crude test of a controversial scheme known as solar geoengineering, which aims to counter climate change by spraying tiny particles into the stratosphere to reflect more of the sun’s heat back into space.

But is what’s in that tube “really what the stratosphere is like?” asks Keutsch, a professor of engineering, chemistry and atmospheric science, as he gestured toward it. “That’s the question. We try to think of everything, but I would argue you never quite know.”

That’s why he and fellow researchers, including Harvard climate scientist David Keith, want to move their experiments out of their toy stratosphere and up into the real one. They hope to conduct a series of scientific balloon flights, the first of which could launch from the Esrange Space Center in Kiruna, Sweden as soon as this summer.

I seriously hope we’ll never get in a situation where this actually has to be done, because I still think this is a very scary concept and something will go wrong.

Frank Keutsch, principal investigator of SCOPEX

The initial flight will simply evaluate whether the aircraft’s equipment and software work properly in the stratosphere, where temperatures can plunge below 50˚ C and the pressure ranges from one tenth to one thousandth of that at sea level. But in subsequent launches, the researchers hope to release small amounts of the sorts of particles that could scatter sunlight.

In a world that’s cutting carbon dioxide emissions too slowly to prevent catastrophic climate change, solar geoengineering might buy some time. But doing it on a large scale could mean messing with planet-wide weather patterns. The effects are unpredictable; in some places, they might even be disastrous.

In the coming weeks, therefore, an independent advisory committee that is reviewing the legal, ethical and environmental issues surrounding the project is expected to determine whether the research group should proceed with the first flight. The committee will also have to rule before any flights that actually release materials, and determine what steps the research team should or must take to engage with the public and regulators.

If those launches are approved—and that’s still a big if—they will be the first geoengineering experiments in the stratosphere. But before the balloons have even left the ground, they’re already drawing criticism.

Too dangerous to use

The idea of cooling the planet by dispersing particles in the atmosphere, dimming sunlight and offsetting some of the warming driven by greenhouse gas emissions, has a precedent: nature already does it.

Major volcanic eruptions such as Mount Pinatubo in 1991 have spewed millions of tons of sulfur dioxide into the air, depressing global temperatures in the years that followed. The sulfur dioxide emitted from coal plants and ships produces measurable cooling effects as well.

To some critics, doing this deliberately as a measure against climate change is reckless even to ponder, let alone experiment with. Some studies have found solar geoengineering could significantly alter rainfall patterns and cut certain crop yields in certain places. On the other hand, other papers have concluded that the environmental side-effects could be small so long as geoengineering is done in a moderate way.

But all of the research done to date, with a few small-scale exceptions, has been conducted in computer models or lab experiments. So Keutsch and his colleagues argue that their balloon trials are a critical next step.

The basic idea for their so-called SCoPEx experiments, first proposed back in 2014, is to launch a balloon equipped with propellers and sensors that would release up to 2 kilograms of sub-micrometer-size particles in a roughly kilometer-long plume. A commercial airliner pumps out similar amounts of material every minute, Keith notes.

Then the balloon will tack around and slowly zigzag through the plume from the opposite direction. Its sensors will attempt to measure how widely the particles disperse, how they interact with other compounds, and how much sunlight they reflect.


Whatever they find can be fed back into computer models, refining our understanding of what spraying hundreds of thousands to millions of tons of materials may do.

At this point, the team hopes to conduct a series of flights over a number of years. At first, they intend to release a fine dust of calcium carbonate—i.e. the principle ingredient of chalk—but eventually the researchers want to test other materials, likely including sulfuric acid (which is a by-product of the sulfur dioxide released from volcanoes).

But some fear even these limited experiments are a step too far.

Wil Burns, co-director of the Institute for Carbon Removal Law & Policy at American University, believes there should be an attempt to reach some kind a global consensus about whether society should ever use such a tool even before outdoor experiments go ahead.

But for him, the answer is no: The environmental impacts are unknown. The challenges of governing such a tool are immense—a single country could carry out solar geoengineering on its own, but all would be affected. And future generations could be forced to manage the effects for hundreds of years. He adds that we can’t know what it will really do at a planetary scale until it’s fully deployed – and at point, we’re stuck with any droughts or other dangers until the effects subside.

Some environmental groups and geoengineering critics are calling on government officials in Sweden, where the first SCoPEx flight would launch from, and the heads of Swedish Space Corporation, which will manage them, to oppose the experiments. They argue not that the research itself presents environmental risks but that it creates a “slippery slope toward normalization and deployment” of a perilous and powerful tool.

Solar geoengineering “is a technology with the potential for extreme consequences, and stands out as dangerous, unpredictable, and unmanageable,” a letter issued by Greenpeace Sweden, Biofuelwatch and other groups reads. “There is no justification for testing and experimenting with technology that seems to be too dangerous to ever be used.”

The reluctant researcher

Keutsch says it’s a “very valid” fear that geoengineering experiments could make its eventual use more likely. As he told me during an interview in his office, he himself thinks geoengineering is the wrong way to address climate change. He compared it to opiates that ease acute pain but lead to other problems like addiction. The far safer, more effective solution would be to rapidly slash greenhouse gas emissions.

But he fears that climate change is so far along and likely to become so disruptive that some desperate nation may move ahead with geoengineering anyway. An earlier Harvard study found that the cost of developing and flying a fleet of specialized planes that could do the job would cost as little as $2 billion a year, putting it within the economic reach of many countries.

Since it’s the only tool that could make any real difference to global temperatures within the period of a political term, it could become an incredibly seductive option in nations suffering through deadly heatwaves, droughts, famines, fires, or floods. Using it without sufficient research would be “very dangerous,” Keutsch says.

Harvard professor Frank Keutsch, principal investigator of SCoPEx.

“People think that because I’m doing geoengineering research I sort of want to do geoengineering,” he says. “My view is actually very strongly that I seriously hope we’ll never get in a situation where this actually has to be done, because I still think this is a very scary concept and something will go wrong.”

“But at the same time, I think better understanding what the risks may be is very important,” he adds. “And I think for the direct research I’m most interested in, if there is a type of material that can significantly reduce risks, I do think we should know about this.”


The team initially hoped to begin balloon flights as early as 2018 in Tucson, Arizona, and subsequently explored plans in New Mexico. They opted to move the first effort to Sweden because of “COVID-19 and other logistical and scheduling challenges,” according to the project website.

Part of the delay was due to the Keutsch team’s decision to set up an independent committee to evaluate the ethical and legal impacts of their proposed experiments. They didn’t have to have one, since the research effort has no federal funding. (Indeed, when the project began, there was no US federal funding for geoengineering research. The project runs on internal Harvard money and donations from individuals and groups including Bill Gates, The William and Flora Hewlett Foundation, The Alfred P. Sloan Foundation, and others.)

But Jane Long, a former associate director at Lawrence Livermore National Laboratory, strongly recommended that an external review committee be created. (She also helped pick its chairperson.) “It was important for the future of this technology that they’re not seen as bad scientists running off to do some experiment without any review,” she says.

Long stresses that the experiments, as first proposed, are very small scale and unlikely to present health or environmental dangers. But the board, she says, forces the researchers to articulate what the work is for and to address public concerns.

The committee has already issued a report providing suggestions on how the research team should communicate with the public before any flights that release particles. Among other things, it recommends creating a briefing book to explain the issues and inviting people who live near the balloons’ flight path to “participate in deliberative dialogue about the experiment itself as well as governance of solar geoengineering research.”

Still, Burns and others argue the committee is missing some crucial voices, including critics of geoengineering research and representatives from poorer countries. And he believes these blind spots are evident in the committee’s initial report. “It assumes, and kind of evinces a bias, that we’re only doing the public engagement to figure out how to get to the next stage in terms of field experiments—and that seems to be creating a kind of foregone conclusion in terms of what will happen and what should happen,” he says.

What they might learn

Keutsch’s team has already run computer simulations exploring how the particles released from their equipment will dissipate into the air. If and when they starting testing this for real, they should be able to measure more precisely how specks of calcium carbonate or sulfuric acid spread out or clump together—a crucial test of how well these materials might work for geoengineering. If the particles are too big, they’ll sink too quickly out of the stratosphere, requiring more materials to scatter the same amount of sunlight.

Another crucial question is how the particles will react with other chemicals in the stratosphere—particularly the calcium carbonate, since it doesn’t occur up there naturally.


The team chose calcium carbonate for two reasons, Keutsch says: sulfates eat away at the protective ozone layer, and while they have a cooling effect at the Earth’s surface, they warm the stratosphere. That could stir up weather patterns in ways that could be hard to foresee. “You are trying to poke the Earth system in ways that I don’t think our models are good at predicting,” Keutsch says.

But calcium carbonate comes with its own unknowns. Those experiments in that glass tube found it is not particularly reactive with the compounds it will encounter in the stratosphere. But how it interacts with other chemicals in the real one could alter how much ultraviolet radiation is absorbed and how much sunlight is scattered.

The observations from the flights could help refine our understanding of how much of these materials may be needed to lower global temperatures, what risks it could pose – or whether it will work at all.

But there will still be real limits on what the researchers can learn from tiny balloon experiments. They won’t be able to detect the longer-term fate of particles released into the stratosphere, because they’ll quickly become too dilute to detect. Moreover, Keutsch acknowledges there are simply some things that can’t be known until someone deploys solar geoengineering at full scale.

“The earth system is so complex,” he says. “I don’t think we can predict entirely. We can’t ever be really sure of what’s going to happen when you do this.”

Lyron Foster is a Hawaii based African American Musician, Author, Actor, Blogger, Filmmaker, Philanthropist and Multinational Serial Tech Entrepreneur.

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Tim Hortons marks two years in China with Tencent investment



Tim Hortons, the Canadian coffee and doughnut giant, has raised a new round of funding for its Chinese venture. The investment is led by Sequoia China with participation from Tencent, its digital partner in China, and Eastern Bell Capital. The round comes two years after Tim Hortons made its foray into China’s booming coffee industry.

Tim Hortons didn’t disclose the amount of its latest fundraise but noted in a social media post that the proceeds will be used for opening more stores, building its digital infrastructure, brand presence, and more.

Tencent, the Chinese social media and entertainment behemoth, first backed the 57-year-old Canadian coffee chain last May. At the time the tie-up was seen as Tencent’s move to counter archrival Alibaba’s alliance with Starbucks to deliver coffee and help the American coffee titan go digital in China.

Tim Horton’s collaboration with the WeChat parent is in a similar vein. It has so far accumulated three million members through its WeChat mini program, a type of lightweight app that runs within the instant messenger. To appeal to young Chinese consumers, Tim Hortons opened an esports-themed cafe with Tencent, China’s biggest gaming company.

Two years into operating in China, Tim Hortons says it has reached storefront-level profitability with a footprint of 150 locations across 10 major cities. It plans to add more than 200 locations in 2021 and reach 1,500 stores nationwide in the next few years.

The dramatic rise and fall of coffee delivery startup Luckin brought the prospects of China’s coffee market to the forefront. Despite the investment frenzy around Luckin and other coffee businesses, coffee drinking still has a relatively low penetration in China compared to countries like the United States and Germany. On the other hand, coffee consumption is growing at a much faster rate of 15% in China, well above the global average of 2%, and is projected to reach 1 trillion yuan ($150 million) in 2025, according to a 2020 report by Dongxing Securities.

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Bessemer Venture Partners closes on $3.3 billion across two funds



Another major VC firm has closed two major rounds, underscoring the long-term confidence investors continue to have for backing privately-held companies in the tech sector.

Early-stage VC firm Bessemer Venture Partners announced Thursday the close of two new funds totaling $3.3 billion that it will be using both to back early-stage startups as well as growth rounds for more mature companies.

The Redwood City-based firm closed BVP XI with $2.475 billion and BVP Century II with $825 million in total commitments.

With BVP XI, it plans to focus on early-stage companies spanning across enterprise, consumer, healthcare, and frontier technologies. 

Its Century II fund is aimed at backing growth-stage companies that Bessemer believes “will define the next century,” and will include both follow-on rounds for existing portfolio companies or investments in new ones.

BVP XI marks Bessemer’s largest fund in its 110-year history. In October 2018, the firm brought in $1.85 billion for its tenth flagship VC fund. This latest fund is its fifth consecutive billion-dollar fund, based on PitchBook data. 

Despite being founded more than 100 years ago, Bessemer didn’t actually enter the venture business until 1965. It’s known for its investments in LinkedIn, Blue Apron and many others, with a current portfolio that includes PagerDuty, Shippo, Electric and DocuSign. Exits include Twitch and Shopify, among many others.

With more money than ever before available for backing startups, the challenge now for VCs is to see how and if they can find (and invest in) whatever will define the next generation of tech. 

“As venture capitalists, we pay too much attention to pattern recognition and matching when in reality, the biggest opportunities exist where those patterns break,” the firm wrote in a blog post today. “Our job is to make perceptive bets on the future, especially those that others will dismiss and ridicule. We are fundamental optimists and strong believers in the power of innovation; our life’s work is putting our reputation, time, and money to help entrepreneurs realize a different future. They’re the ones pioneering something entirely new and obscure – a technology, a business model, a category.

In addition to announcing the new funds, Bessemer also revealed today that it’s brought on five new partners including Jeff Blackburn, who joins after a 22-year career at Amazon, alongside the promotion of existing investors Mary D’Onofrio, Mike Droesch, Tess Hatch, and Andrew Hedin.

Most recently at Amazon, Blackburn served as senior vice president of worldwide business development where he oversaw dozens of Amazon’s minority investments and more than 100 acquisitions across all business lines – including retail, Kindle, Echo, Alexa, FireTV, advertising, music, streaming audio & video, and Amazon Web Services.  

“Having been part of Amazon for more than two decades, I’m excited to begin a new chapter helping customer-focused founders build breakthrough companies,” said Blackburn in a written statement.  “I’ve known the Bessemer team for many years and have long admired their strategic vision and success backing early-stage ventures.” 

With the latest changes, Bessemer now has 21 partners and over 45 investors, advisors, and platform “team members” located in Silicon Valley, San Francisco, Seattle, New York, Boston, London, Tel Aviv, Bangalore, and Beijing. 

“At Bessemer, there’s no corner office or consensus; every partner has the choice, independently, to pen a check. This kind of accountability and autonomy means a founder is teaming up with a partner and board director who thoroughly understands your business and can respond quickly and decisively,” the firm’s blog post read.

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Daily Crunch: Twitter announces ‘Super Follow’ subscriptions



Twitter reveals its move into paid subscriptions, Australia passes its media bargaining law and Coinbase files its S-1. This is your Daily Crunch for February 25, 2021.

The big story: Twitter announces ‘Super Follow’ subscriptions

Twitter announced its first paid product at an investor event today, showing off screenshots of a feature that will allow users to subscribe to their favorite creators in exchange for things like exclusive content, subscriber-only newsletters and a supporter badge.

The company also announced a feature called Communities, which could compete with Facebook Groups and enable Super Follow networks to interact, plus a Safety Mode for auto-blocking and muting abusive accounts. On top of all that, Twitter said it plans to double revenue by 2023.

Not announced: launch dates for any of these features.

The tech giants

After Facebook’s news flex, Australia passes bargaining code for platforms and publishers — This requires platform giants like Facebook and Google to negotiate to remunerate local news publishers for their content.

New Facebook ad campaign extols the benefits of personalized ads — The sentiments are similar to a campaign that Facebook launched last year in opposition to Apple’s upcoming App Tracking Transparency feature.

Startups, funding and venture capital

Sergey Brin’s airship aims to use world’s biggest mobile hydrogen fuel cell — The Google co-founder’s secretive airship company LTA Research and Exploration is planning to power a huge disaster relief airship with an equally record-breaking hydrogen fuel cell.

Coinbase files to go public in a key listing for the cryptocurrency category — Coinbase’s financials show a company that grew rapidly from 2019 to 2020 while also crossing the threshold into unadjusted profitability.

Boosted by the pandemic, meeting transcription service raises $50M — With convenient timing, added Zoom integration back in April 2020.

Advice and analysis from Extra Crunch

DigitalOcean’s IPO filing shows a two-class cloud market — The company intends to list on the New York Stock Exchange under the ticker symbol “DOCN.”

Pilot CEO Waseem Daher tears down his company’s $60M Series C pitch deck — For founders aiming to entice investors, the pitch deck remains the best way to communicate their startup’s progress and potential.

Five takeaways from Coinbase’s S-1 — We dig into Coinbase’s user numbers, its asset mix, its growing subscription incomes, its competitive landscape and who owns what in the company.

(Extra Crunch is our membership program, which helps founders and startup teams get ahead. You can sign up here.)

Everything else

Paramount+ will cost $4.99 per month with ads — The new streaming service launches on March 4.

Register for TC Sessions: Justice for a conversation on diversity, equity and inclusion in the startup world — This is just one week away!

The Daily Crunch is TechCrunch’s roundup of our biggest and most important stories. If you’d like to get this delivered to your inbox every day at around 3pm Pacific, you can subscribe here.

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