My inbox and calendar have been filled all year with press releases and requests to chat about new carbon removal technologies, artificial intelligence and its attendant energy demand, novel battery designs, advances in fission and fusion, and investors’ ever-present concerns about how to get all of this to market in time to make a real dent in the climate crisis (and also, you know, a profit).
I wrote about a lot of it — but not all of it, and much of the stuff that got left out is no less worthy of your attention than the stuff that made it. So here I present a roundup of the climate technologies that you might not have read about in Heatmap this year, but that have investors, academics, and the climate world at large buzzing as we look toward 2025.
1. Green methanol for sustainable shipping fuels
This fall when I spoke with Amy Duffuor, a co-founder and partner at the venture capital firm Azolla Ventures, she told me that her firm, which is focused on “overlooked and neglected” climate solutions, has been fascinated by the shipping industry. Because while aviation and shipping each account for about 3% of global emissions, decarbonizing flight seems to get the bulk of the attention. “Sometimes it’s hard for people to imagine what they don’t see or what they’re not interacting with on a day to day basis,” Duffuor told me.
This fall, the firm co-led a $4.5 million seed round of investment in clean fuels producer Oxylus Energy, which converts carbon dioxide into green methanol for use in shipping and other transportation fuels. The tech relies on renewable-powered electrolyzers similar to those used to make green hydrogen, but the company’s secret sauce is a special catalyst that can convert carbon dioxide into methanol at low temperature and pressure, making the whole process more efficient and more economical than ever before.
Duffuor told me that green methanol has a leg up on other clean fuels such as green hydrogen, which has a low energy density, or green ammonia, which is highly toxic and corrosive. While supply of all of these is still limited and costly, Duffuor said that retrofitting an engine to run on green methanol is much simpler than adapting to other alternative fuels, which is why it’s already being done on a small scale today. Indeed, shipping giant Maersk has a number of green methanol boats in its fleet, one of which completed the world’s first green methanol-powered voyage last fall.
2. Solar geoengineering
Long considered “one of climate science’s biggest taboos,” according to Heatmap’s own Robinson Meyer, geoengineering had a big 2024, and it looks poised to be taken increasingly seriously. In fact, one investor I spoke with this month, Lee Larson of Piva Capital, which focuses on decarbonizing heavy industry, told me he foresees a splashy but undeniably controversial funding announcement coming in the near future. “I don’t think it’s going to be Piva, but someone is going to take a bet on this, and there’s going to be a big funding round for a startup in this space,” he predicted. “Because there’s enough interested people with deep pockets that have been thinking about this space for someone to raise money off of it.”
But if nothing else, this year proved that the backlash would be swift. In June, the city council in the small town of Alameda, California, shut down testing of a solar geoengineering device that could one day be used for “marine cloud brightening” — that is, spraying aerosols into the sky to enable clouds to reflect more sunlight away from Earth — and Harvard University abandoned another solar geoengineering project, which aimed to study how aerosol plumes behave in the stratosphere. At the same time, though, the nonprofit Environmental Defense Fund announced that it would fund research into solar geoengineering to help inform policymakers should it one day become regulated, and the UK also committed to supporting research into various solar geoengineering pathways, including conducting outdoor experiments.
“There’s a growing understanding that, on a per unit of warming avoidance basis, this is just way cheaper than carbon dioxide removal solutions,” Larson told me. From his perspective, the world needs to support this type of research lest a layperson, a billionaire, or a small nation choose to go rogue. “Just given how cheap it is, given how little we know about it, that’s a poor combination — because the chance of someone doing something with a lot of unintended consequences goes up and up.”
3. Floating solar
The idea is pretty straightforward — install solar panels that can float on the surface of reservoirs, canals, lakes, and the like — but this year it really began to pick up steam. There are myriad benefits to this solution: eliminating land use controversies, built-in temperature regulation (water keeps the panels cool, thus increasing their efficiency), and reducing evaporation from the water bodies. A paper published in Nature this June found that floating solar could meet, on average, 16% of countries’ total energy needs.
And countries big and small are taking note. While there aren’t a lot of specialized floating solar startups seeking VC funding, governments as well as traditional solar manufacturers and project developers are stepping up. The U.S. Department of the Interior announced in April that it’s investing $19 million to install panels over irrigation canals in California, Oregon, and Utah. Zimbabwe recently secured $250 million from the African Export-Import Bank to install floating solar on the world’s largest man-made lake, while China turned on the largest offshore solar farm in the world in November. Taiwan and India have also already deployed large installations, and have plans for more.
I spoke with the lead author of the Nature paper, Dr. Iestyn Woolway of the UK-based Bangor University, way back in June about floating solar’s decarbonization potential. Even he was “quite surprised with the number of countries that could meet a sizable fraction of the energy demands by [floating photovoltaics],” he told me. His modeling shows that Bolivia, for example, could meet about 80% of its energy demand with floating solar, while Ethiopia could meet 100% of its demand, with extra energy to spare.
The next step, he said, is gaining a deeper understanding of the ecological impacts of this technology. “Even if you do cover a water body by something small, like 10%, we don’t know what knock-on effect that would have,” he said.
4. Soil carbon sequestration
Soils are some of the world’s most effective carbon sinks, and sustainable farming techniques can enhance soil’s natural carbon sequestration potential. Thus, soil carbon sequestration plays at the intersection of the fuzzy and buzzy regenerative agriculture space and the increasingly scientifically rigorous carbon dioxide removal sector, with its carbon crediting schemes and verification requirements. One investor I spoke with, Amy Francetic of Buoyant Ventures, is eager to find and back a company that can merge these two worlds. “If you could figure out how to sink carbon in a farm and do that in a way that is easy to measure and validate, we don’t have a good solution for that today,” she told me.
As of now, Francetic said, startups are going about this problem by doing labor intensive and expensive soil sampling and “marrying that with geospatial data to try to measure what climate benefits there are of changing certain agricultural practices, doing different row crops, changing the crop rotation, the amount of inputs you put into the crops.” Many have pitched Buoyant on their methodologies for bridging satellite data with soil sampling data, but thus far she’s passed. “None of them have, I think, met the standard of reliability that the financial industry would back from a carbon credit standpoint,” she explained. “That might be one of these holy grail things. If somebody could really do that, it could be very impactful.”
5. Parametric insurance products
I’ll be honest, before this year I didn’t know what parametric insurance was. But since it came up time and again in conversations with investors about extreme weather and the necessity of climate resilience and adaptation measures, I decided to dig in. Here’s what parametric insurance is: an insurance product that automatically provides rapid payouts to customers in the case of natural disasters or weather events, assuming these events exceed a predefined limit. For example, a policyholder might be paid if the rainfall, wind speed, or temperature of a particular weather event is above or below a certain threshold, with the amount tied to how much the measurement deviates from the limit, not the damages incurred.
With extreme weather events getting more frequent and more intense due to climate change, this has given rise to a crop of startups that can leverage sensors, satellites, and artificial intelligence to quickly and accurately measure the extent of these events, thus enabling parametric insurance for a host of new customers. To name a few companies that have taken advantage: There’s Floodbase and FloodFlash (both focusing on flood insurance, naturally), which have each raised over $10 million in Series A financing; FloodFlash made a series of rapid payouts this year following storms in the UK, getting policyholders their money in as little as 10 hours after the water level exceeded its threshold. There’s Arbol, which protects against a host of weather events from drought to heat waves and cold snaps, and raised a $40 million Series B round this year. And there’s Pula, which helps provide parametric insurance to small-holder farmers in emerging markets, and raised a $20 million Series B round this year.
“This is affecting everybody,” Clea Kolster of Lowercarbon Capital, which led Floodbase’s Series A round, told me when we met at this year’s San Francisco Climate Week. “So how do you actually make sure that people have coverage for it and can continue to have as close to livable lives as possible, even when they’re subject to more frequent extreme weather events?” Investors know the storms are going to keep coming, so this category of adaptation tech is only set to grow.
A nickel mine in Indonesia. Ulet Ifansasti/Getty Images 
