The next generation of nuclear reactors is getting more advanced. Here’s how.

This article is from The Spark, MIT Technology Review’s weekly climate newsletter. To receive it in your inbox every Wednesday, sign up here.

I’ve got nuclear power on the brain this week. 

The workings of nuclear power plants have always fascinated me. They’re massive, technically complicated, and feel a little bit magic (splitting the atom—what a concept). But I’ve reached new levels of obsession recently, because I’ve spent the past week or so digging into advanced nuclear technology. 

Advanced nuclear is a mushy category that basically includes anything different from the commercial reactors operating now, since those basically all follow the same general formula. And there’s a whole world of possibilities out there. 

I was mostly focused on the version that’s being developed by Kairos Power for a story (which was published today, check it out if you haven’t!). But I went down some rabbit holes on other potential options for future nuclear plants too. So for the newsletter this week, let’s take a peek at the menu of options for advanced nuclear technology today. 

The basics

Before we get into the advanced stuff, let’s recap the basics.

Nuclear power plants generate electricity via fission reactions, where atoms split apart, releasing energy as heat and radiation. Neutrons released during these splits collide with other atoms and split them, creating a chain reaction.

In nuclear power plants today, there are basically two absolutely essential pieces. First, the fuel, which is what feeds the reactions. (Pretty obvious why this one is important.) Second, it’s vital that the chain reactions happen in a controlled manner, or you can get into nuclear meltdown territory. So the other essential piece of a nuclear plant is the cooling system, which keeps the whole thing from getting too hot and causing problems. (There’s also the moderator and a million other pieces, but let’s stick with two so you’re not reading this newsletter all day.)

In the vast majority of reactors on the grid today, these two components follow the same general formula: the fuel is enriched uranium that’s packed into ceramic pellets, loaded into metal pipes, and arranged into the reactor’s core. And the cooling system pumps pressurized water around the reactor to keep the temperature controlled.  

But for a whole host of reasons, companies are starting to work on making changes to this tried-and-true formula. There are roughly 70 companies in the US working on designs for advanced nuclear reactors, with six or seven far enough along to be working with regulators, says Jessica Lovering, cofounder and co-executive director at the Good Energy Collective, a policy research organization that advocates for the use of nuclear energy.

Many of these so-called advanced technologies were invented and even demonstrated over 50 years ago, before the industry converged on the standard water-cooled plant designs. But now there’s renewed interest in getting alternative nuclear reactors up and running. New designs could help improve safety, efficiency, and even cost. 

Coolant

Alternative coolants can improve on safety over water-based designs, since they don’t always need to be kept at high pressures. Many can also reach higher temperatures, which can allow reactors to run more efficiently. 

Molten salt is one leading contender for alternative coolants, used in designs from Kairos Power, Terrestrial Energy, and Moltex Energy. These designs can use less fuel and produce waste that’s easier to manage. 

Other companies are looking to liquid metals, including sodium and lead. There are a few sodium-cooled reactors operating today, mainly in Russia, and the country is also at the forefront in developing lead-cooled reactors. Metal-cooled reactors share many of the potential safety benefits of molten-salt designs. Helium and other gases can also be used to reach higher temperatures than water-cooled systems. X-energy is designing a high-temperature gas-cooled reactor using helium. 

Fuel

Most reactors that use an alternative coolant also use an alternative fuel.  

TRISO, or tri-structural isotropic particle fuel, is one of the most popular options. TRISO particles contain uranium, enclosed in ceramic and carbon-based layers. This keeps the fuel contained, keeping all the products of fission reactions inside and allowing the fuel to resist corrosion and melting. Kairos and X-energy both plan to use TRISO fuel in their reactors. 

Other reactors use HALEU: high-assay low-enriched uranium. Most nuclear fuel used in commercial reactors contains between 3% and 5% uranium-235. HALEU, on the other hand, contains between 5% and 20% uranium-235, allowing reactors to get more power in a smaller space. 

Size

I know I said I’d keep this to two things, but let’s include a bonus category. In addition to changing up the specifics of things like fuel and coolant, many companies are working to build reactors of different (mostly smaller) sizes.

Today, most reactors coming on the grid are massive, in the range of 1,000 or more megawatts—enough to power hundreds of thousands of homes. Building those huge projects takes a long time, and each one requires a bespoke process. Small modular reactors (SMRs) could be easier to build, since the procedure is the same for each one, allowing them to be manufactured in something resembling a huge assembly line. 

NuScale has been one of the leaders in this area—its reactor design uses commercial fuel and water coolant, but the whole thing is scaled down. Things haven’t been going so well for the company in recent months, though: its first project is pretty much dead in the water, and it laid off nearly 30% of its employees in early January. Other companies are still carrying the SMR torch, including many that are also going after alternative fuels and coolants. 

If you’re hungry for more advanced nuclear news, take a look at my story on Kairos Power. You can also check out some of our recent stories from the vault. 

Related reading

Germany shut down the last of its nuclear reactors last year. Here’s a look at the power struggle over nuclear power in the country.

MIT runs a small test reactor on campus, and I got to take a look inside. See how this old reactor could spark new technology.

We were promised smaller nuclear reactors, but so far that promise hasn’t really materialized. What gives?

We named NuScale one of our Climate Tech Companies to Watch in 2023. We’re definitely … watching, given the recent bumps in the road. 

6 full-size perovskite tandem cells in a metal assembly carriage

SWIFT SOLAR

Another thing

Super-efficient solar cells are on our list of the 10 Breakthrough Technologies of 2024. (If you haven’t seen that list, you can find it here!) By sandwiching other materials with traditional silicon, tandem perovskite solar cells could help cut solar costs and generate more electricity. 

But what will it actually take to get next-generation solar technology to the market? Here’s a look at a few of the companies working to make it happen.

Keeping up with climate  

Hertz was billing itself as a leader in renting out electric vehicles (remember that Tom Brady commercial?). Now the company is selling off a third of its EV fleet. (Tech Crunch)

A mountain of clothes accumulated in the desert in Chile. Then it caught fire. This is a fascinating deep dive into the problem of textile waste. (Grist)

New uranium mines will be the first to begin operations in the US in eight years. The mines could help bring more low-carbon nuclear power to the grid, but they’re also drawing sharp criticism. (Inside Climate News)

Researchers at Microsoft and a US national lab used AI to find a new candidate material for batteries. It could eventually be used in batteries to reduce the amount of lithium needed to build them. (The Verge)

→ I talked about this and other science news of the week on Science Friday. Give it a listen! (Science Friday)

Animals are always evolving. A few lucky ones might even be able to do it fast enough to keep up with climate change. (Hakai Magazine)

All that new renewable energy coming onto the grid is helping make a dent in US emissions. Buildout of clean energy cut greenhouse-gas emissions by nearly 2% in 2023. (Canary Media)

The Biden administration will fine oil and gas companies for excess methane emissions. Penalties for emitting this super-powerful greenhouse gas are part of the landmark climate bill passed in 2023. (New York Times)

Texas has had a host of upgrades to its electric grid in the years since a powerful storm devastated the state in 2021. Now experts are watching to see how the grid holds up against cold weather this week. (Washington Post)

Three climate technologies breaking through in 2024

This article is from The Spark, MIT Technology Review’s weekly climate newsletter. To receive it in your inbox every Wednesday, sign up here.

Awards season is upon us, and I can’t get enough. Red-carpet fashion, host drama, heartwarming speeches—I love it all.

I caught the Golden Globes last weekend, and the Grammys and Oscars aren’t far off. But the best awards, in my humble opinion, are the 10 Breakthrough Technologies, MIT Technology Review’s list of the tech that’s changing our world. 

This year’s list dropped on Monday, and I’m delighted to share that not one, not two, but three climate tech items are featured. So for the newsletter this week, let’s take a look at a few of these award-winning technologies you need to know about. (And to honor awards season, I’ll also be assigning them to bonus—and completely unofficial—categories.)

Super-efficient solar cells

Winner: Best Supporting Actor

Solar panels are among the most important, and perhaps the most recognizable, tools to address climate change. But one next-generation solar technology could help solar power get even more efficient, and cheaper: perovskite tandem solar cells. 

Most solar cells use silicon to soak up sunlight and transform it into electricity. But other materials can do this job too, including perovskites, a class of crystalline materials. And because perovskites and silicon absorb different wavelengths of light, the two materials can be stacked like a sandwich to make one super-efficient cell. 

Because of their outstanding support for traditional silicon solar materials, super-efficient perovskite tandem cells are my winner for this year’s Best Supporting Actor award. 

There are definitely barriers to commercializing this technology: perovskites are tricky to manufacture and have historically degraded quickly outside in the elements. But some companies say they’re closer than ever to using the materials to transform commercial solar. Read more about the technology here

Enhanced geothermal systems

Winner: Best New Artist

Sucking heat out from the earth is one of the oldest tricks in the book—there’s evidence that humans were using hot springs for heat more than 10,000 years ago. 

We’ve since leveled up, using geothermal energy to produce electricity. But a specific set of factors is needed to harness the energy radiating out of the planet’s core: heat close to the surface, permeable rock, and underground fluid. 

This narrows the potential sites for usable geothermal energy significantly, so a growing number of projects are working to widen access with so-called enhanced geothermal systems. 

An enhanced geothermal system is essentially a human-created geothermal energy source. This often involves drilling down into rock and pumping fluid into it to open up fractures. We’ve seen some recent progress in this field from a handful of companies, including Fervo Energy, which started up a massive pilot facility in 2023 (and made our list of 15 Climate Tech Companies to Watch). 

Because of its spirit of reinvention and innovation, enhanced geothermal systems are my pick for this year’s Best New Artist Award. 

Some of the biggest projects coming are still a few years from coming online, and it could be tough to scale construction on these plants in some places. But enhanced geothermal is definitely a field to keep an eye on. Read more in my colleague June Kim’s write-up here

Heat pumps

Winner: Lifetime Achievement

Last, but certainly not least, we have the venerable heat pump. These devices, which can cool and heat using electricity, are a personal favorite climate technology of mine. 

Heat pumps are super efficient, sometimes almost seeming to defy the laws of physics. They don’t really break any laws, physical or otherwise, as I outlined in a deep dive into how the technology works last year.

While they’re not exactly new, heat pumps are definitely breaking through in a new way. The technology outsold gas furnaces for the first time in the US last year, and sales have been climbing around the world. Globally, heat pumps have the potential to cut emissions by 500 million metric tons in 2030—as much as pulling all the cars in Europe today off the roads. 

For their long-standing and ongoing contributions to decarbonization, heat pumps are my choice for this year’s Lifetime Achievement Award. 

It’s going to be tough to get heat pumps into all the places they need to go to meet climate goals. For more on all things heat pumps, check out my write-up here. 

Congratulations to all our winners! Be sure to check out the rest of the list. It includes everything from wearable headsets to innovative new CRISPR treatments. 

And if you’d like to weigh in on one more award, you can vote for our reader-chosen 11th breakthrough technology here. The candidates are some of the other items we considered for the list. I don’t want to unfairly influence you, but you know my heart always goes with batteries, so feel free to vote accordingly …  

Related reading

Technology is always changing. Don’t miss our list of the technologies breaking through in 2024.

Perovskites were supposed to change the solar world. What’s the holdup?

This startup showed that its underground wells can be used as a massive battery.

Everything you need to know about the wild world of heat pumps.

Another thing

an Orsted wind turbine off the coast of Block Island

AP PHOTO/JULIA NIKHINSON

It’s been a turbulent time for offshore wind power. Projects are getting delayed and canceled left and right, it seems. 

In 2024, some big moments could determine whether these troubles are more of a bump in the road or a sign of more serious issues. For everything you should watch out for in offshore wind, check out my latest story here.

Keeping up with climate  

It’s officially official—2023 was the hottest year on record, according to the EU’s climate service. Check out the details and some stunning graphics on the record-breaking year. (BBC)

A national lab in California made waves in late 2022 when it achieved a huge milestone for fusion research. You may not know that the facility actually had a massive fusion reactor in the 1980s that never got switched on. (MIT Technology Review)

→ Here’s what’s coming next for fusion research, according to the lab’s current director. (MIT Technology Review)

India is rushing to meet growing demand for electricity, and the country is turning to coal to do it. The government plans to roughly double coal production by 2030. (Bloomberg)

One person’s wastewater is another one’s … heat? New systems can harness the heat in wastewater to heat whole neighborhoods. (BBC)

Norway will open up parts of the Norwegian Sea for seabed mining exploration. The country joins nations including Japan, New Zealand, and Namibia that are considering allowing this new industry to operate in their waters. (New York Times)

→ Seabed mining could be a new source of materials for batteries. But environmentalists are worried about the potential harm. (MIT Technology Review)

Lack of charging infrastructure is a huge barrier to EV adoption. Here are three ways to encourage new chargers in charging deserts. (Canary Media)

Rising temperatures means beavers are moving north—and they’re causing trouble. Specifically, the rodents are creating a feedback loop that’s thawing the ground and disrupting ecosystems. (The Guardian)

Chinese automaker BYD is set to take the world by storm. The company sold more plug-in hybrids and EVs than Tesla did in 2023, and is set to continue its rapid growth this year. (Bloomberg)→ BYD was one of our climate tech companies to watch in 2023. (MIT Technology Review)

2023 is breaking all sorts of climate records 

This article is from The Spark, MIT Technology Review’s weekly climate newsletter. To receive it in your inbox every Wednesday, sign up here.

This has been quite the year for climate news, with weather disasters, technological breakthroughs, and policy changes making headlines around the world. There’s an abundance of bad news, but there are also some glimmers of hope, if you know where to look.

It’s a lot to make sense of, so for this last newsletter of 2023, let’s take a look back at the year, and let’s do it in data. A “climate wrapped,” if you will. 

A new record on emissions (again)

Technically, we can’t draw definitive conclusions about 2023 just yet. But it’s pretty evident that we’re on track for yet another record year when it comes to greenhouse-gas emissions from fossil fuels.

Carbon dioxide emissions from fossil fuels are expected to hit 36.8 billion metric tons in 2023, according to the Global Carbon Budget report, which was released earlier this month. That’s just over 1% higher than last year’s levels.

Hitting another record high for emissions isn’t the best news. Ideally, this line would be going in the other direction, and quickly. 

The story isn’t the same everywhere, though. The US and Europe, for instance, are actually seeing slight decreases in carbon pollution (though these places are among the highest historical emitters). China and India are seeing emissions growth of around 4% and 8%, respectively. 

But that growth could be slowing down soon, and some analysts say that within the next few years we could be nearing peak emissions (the moment when they turn around and start going down). I’ll believe it when I see it. 

It’s getting hot in here

Not only are we seeing record-high emissions, but 2023 is almost certainly going to be the hottest year on record, too. The year through November averaged just under 1.5 °C (or about 2.6 °F) hotter than preindustrial levels.

The warming is noticeable even compared with the last few decades. November was 0.85 °C warmer than the average November was in the 1990s. 

Wherever you look, from the air to the ocean, the planet is heating up, and these rising temperatures and other changing weather patterns have cascading effects, as we saw firsthand in 2023. 

Sea ice hit new low levels. Historic wildfires in Canada brought oppressive smoke sweeping down the east coast of the US. Thousands died in flooding in Libya, and a years-long drought in the Horn of Africa has left millions facing water and food shortages. Name any type of climate disaster you can think of, and one of those probably broke records, somewhere in the world, in 2023. 

Looking back, I think this year I saw a trend that’s been building for the past couple of years: a growing number of people are being directly and dramatically affected by climate change. It’s pushing awareness that climate change isn’t some theoretical future possibility, but something happening in the present tense.

Money money money

It’s not possible to take a look back at this year without talking about bad news. But there are some positives too, I promise! 

For one thing, this year also saw record investment in clean energy, with global total spending of $1.7 trillion. (Yes trillion, with a “t.”) 

Investment in clean energy has been outpacing investment in fossil fuels for a while now, but the gap is starting to widen, with growing amounts of spending on technologies like solar and wind power and energy storage. In fact, solar power alone attracted more investment than fossil fuels for the first time.

The current state of the climate is pretty grim, and it’s important to take note of that and be realistic about where we are and what still needs to happen. But these bright spots of climate news are around, if you know where to look. 

That’s why the MIT Technology Review climate team put together some of the good news we saw in the climate world this year. You can find out more about what’s giving us hope in our new story here. 

Related reading

While we’re looking back, let’s reminisce about some of our top climate and energy stories of 2023. 

Keeping up with climate  

Fewer EVs will qualify for tax credits soon in the US, as new restrictions kick in on January 1. Tesla’s Model 3 and Ford’s Mustang Mach-E will be among those ruled out, according to the automakers. (New York Times)

New details about a tax credit in last year’s climate bill reveal a surprising winner: thermal energy storage. Qualifying for the credits could help these alternative energy storage methods break into the market. (Canary Media)

→ Here’s why bricks are a hot new energy storage technology. (MIT Technology Review)

Lab-grown-meat companies like Upside Foods have raked in billions of dollars in funding promising healthy, climate-friendly meat without the animals. But so far, there’s not much to show for it, and lots of challenges with scaling ahead. (Bloomberg

There’s a huge backlog of clean energy projects waiting to connect to the grid in the US. This delay could put 2030 clean-energy targets out of reach for many states. (Canary Media)

After an emissions scandal, automaker Volkswagen agreed to spend $2 billion funding public EV charging stations. Now, those chargers are unreliable—yes, even more so than other public charging networks. (Washington Post)

By the end of the decade, many batteries will need to have a passport—a digital record of their source materials and history. (Quartz)

Carbon removal has gone from a wild idea to a hot topic. Some scientists think that’s a problem, as companies and governments are using this unproven technology to continue with business as usual rather than making hard cuts to emissions. (E&E News)

→ Here’s why some experts say the world is thinking about carbon removal all wrong. (MIT Technology Review)

Despite overwhelming evidence that climate change is real, some people still fall for conspiracy theories. There’s a whole host of reasons why. (Grist)

→ If you’re looking to broach the subject, here are my tips for talking about climate technology over the holidays. (MIT Technology Review)

The two words that pushed international climate talks into overtime

This article is from The Spark, MIT Technology Review’s weekly climate newsletter. To receive it in your inbox every Wednesday, sign up here.

The annual UN climate negotiations at COP28 in Dubai have officially come to a close. Delegates scrambled to get a deal together in the early morning hours, and the meetings ended a day past their scheduled conclusion (as these things tend to). 

If you’ve tuned out news from the summit, I don’t really blame you. The quibbles over wording—“urges” vs. “notes” vs. “emphasizes”—can all start to sound like noise. But these talks are the biggest climate event of the year, and there are some details that are worth paying attention to. 

We’ve seen agreements on methane and renewables, and big progress on an international finance deal. And, of course, there was the high-profile fight about fossil fuels. As negotiators wrap up and start their treks home, let’s take a beat to sort through what happened at COP28 and why all these political fights matter for climate action.

What’s the point of these meetings anyway? 

The UN Conference of the Parties (COP) meetings are an annual chance for negotiators from nearly 200 nations to set goals and make plans to address climate change. 

You might be familiar with the outcome of one of these meetings: eight years ago COP21 gave us the Paris Agreement, the international treaty that set a goal to limit global warming to 1.5 °C (2.7 °F) over preindustrial levels.

This year’s meeting comes at a crucial time for the Paris Agreement. Part of that treaty requires the world to put together a progress report on climate change, called the global stocktake. It’s supposed to happen every five years, and the first one was scheduled to finish up at this year’s COP. 

What were the big agreements from the meetings? 

1. On the first day of the talks, there was a big announcement about a loss and damage fund. This is money that richer nations put into a pool to help pay for damages caused by climate change in more vulnerable nations. 

You may remember that the creation of this fund was a major topic at last year’s COP27 in Egypt. The urgency was spurred by a collection of climate disasters, including particularly devastating floods in Pakistan in August 2022. 

Now there’s some money going into the account: at least $700 million pledged by wealthy nations.

There are some caveats, of course. The agreement is still short on details, missing anything like financial targets or rules about how nations will put money in. In fact, there’s currently no requirement for wealthy nations to contribute at all, and the pledged money is a fraction of what many scientists say is really needed to pay for the damage caused by climate change. (Some estimates put that number at $100 billion annually.)

2. Over 100 countries pledged to triple renewable energy capacity and double energy efficiency by 2030. In addition, the US and 20 other countries signed a pledge to triple global nuclear capacity by 2050. 

3. Finally, 50 oil and gas companies pledged to virtually eliminate methane leaks from their operations by 2030. Methane is a powerful greenhouse gas, and plugging up accidental leaks from oil and gas production is seen as an easy way to cut climate pollution. 

The companies that signed this pledge, which included ExxonMobil and Saudi Aramco, represent 40% of global production. 

Some analysts have pointed out that the pledge will have a pretty limited effect. Most human-caused methane emissions come from agriculture, after all. And accidental methane emissions aren’t the biggest problem fossil-fuel companies cause, by a long shot. The majority of emissions from fossil-fuel companies isn’t from their operations but from their products.

What was holding things up? 

In two words: fossil fuels. 

I wrote in the newsletter a couple of weeks ago about how fossil fuels were going to loom large over these talks, not least because they’re being hosted in the UAE, a nation whose wealth relies heavily on them. The leader of the talks (and head of the UAE’s national oil company) has lived up to that prediction, questioning the scientific reasoning behind the calls to eliminate fossil fuels

As delegates worked to put the final agreement together, a sticking point in the debate was how fossil fuels would be represented. Earlier versions of the draft text called for phasing them out. But many nations, including the UAE, objected to this sort of language. And these meetings run by consensus: everybody has to sign off on the final agreement. 

So in the final version, the language was watered down. The pivotal paragraph now calls on parties to take a series of actions, including “transitioning away from fossil fuels in energy systems, in a just, orderly and equitable manner, accelerating action in this critical decade, so as to achieve net zero by 2050 in keeping with the science.”  

In a way, this bit is a win, since it’s the first COP agreement that even mentions fossil fuels by name. (The bar is truly on the floor.) 

Ultimately, the exact wording of a COP agreement probably won’t be the thing to spur anybody into real action. Rather, the state of the world’s attitude toward climate change is reflected in this agreement: there’s a growing acknowledgement that something needs to change in our relationship with fossil fuels. But there’s not a wide enough consensus yet on the speed of that change, or what that relationship should look like as we pursue ambitious climate goals. 

Maybe next year. 

Another thing

The carbon removal industry is starting to take off, but some experts are warning that it’s headed in the wrong direction. 

There’s a growing signal that the world may have to remove billions of tons of carbon dioxide from the atmosphere to limit global warming. But in a new essay, two former US Department of Energy staffers argue that the emergence of a for-profit sector could actually spell danger for the technology’s ability to help meaningfully address climate change. 

Get all the details in the latest story from my colleague James Temple.

Keeping up with climate  

Silicon powder could be the key to longer EV range and faster charging. Battery giant Panasonic will use silicon material from US-based startup Sila to build new EV batteries. (Wired)

→ Sila’s material debuted in a much smaller product in 2021. (MIT Technology Review)

Not the potatoes! Heavy rains have been bad news for European potato harvesting, sending prices soaring. Thanks, climate change. (Bloomberg)

Repairing EV batteries can be dangerous and difficult. But some mechanics want to do it anyway to save customers money and keep older EVs on the roads. (Grist)

This startup wants to sprinkle rock dust over farmland for carbon removal. (Wired)

Public (non-Tesla) EV chargers in the US can be unreliable, to put it lightly. Here’s how $7.5 billion in federal funding aims to change that. (Canary Media

Two- and three-wheelers are going electric in nations across Asia and Africa. And these small vehicles are having a big impact, making up the majority of reduction in oil demand as transportation goes electric. (New York Times)

→ Gogoro is building a massive network of battery-swappable electric scooters. (MIT Technology Review)

Animal agriculture is a big contributor to climate change, but convincing meat eaters to cut back isn’t easy. If you want to get more people to eat plant-based foods, don’t call them “plant-based.” Much less “vegan.” (Washington Post)

There was one permitted offshore wind farm in progress in the US Great Lakes. Now, the project is on hold. (Inside Climate News)

How carbon removal technology is like a time machine

This article is from The Spark, MIT Technology Review’s weekly climate newsletter. To receive it in your inbox every Wednesday, sign up here.

If you could go back in time, what would you change about your life, or the world?

The idea of giving myself some much-needed advice is appealing (don’t cut your own bangs in high school, seriously). But we can think bigger. What about winding the clock back on the emissions that cause climate change? 

By burning fossil fuels, we’ve released greenhouse gases by the gigaton. There’s a lot we can (and need to) do to slow and eventually stop these planet-warming emissions. But carbon removal technology has a different promise: turning the clock back. 

Well, sort of. Carbon removal can’t literally take us back in time. But this time-machine analogy for thinking about carbon removal—specifically when it comes to the scale that will be needed to make a significant dent in our emissions—is a favorite of climate scientist David Ho, who I spoke to for my latest story. So for the newsletter this week, let’s consider what it might take for carbon removal to take us back far enough in time to reverse our mistakes (emissions-related ones, anyway). 

The world is on track to hit a new record for carbon dioxide emissions due to fossil fuels, with the global total expected to reach 36.8 billion metric tons this year, according to the newest edition of the Global Carbon Budget Report.

For the first time this year, the report included another total: how much carbon dioxide was sucked out of the atmosphere by carbon removal technologies. In 2023, carbon removal is expected to total around 10,000 metric tons. 

That’s obviously a lot less, but exactly how much less can be hard to grasp, as Ho points out. “I think humans (myself included) have a hard time with orders of magnitude, like the difference between thousands, millions, and billions,” he told me in an email. 

One solution Ho has come up with is putting things in terms of time. It’s something we intuitively have a handle on, which can make big numbers easier to understand. A thousand seconds is around 17 minutes. A million seconds is about 11 days. A billion seconds is nearly 32 years. 

Since time is a bit easier to grasp, when Ho talks about carbon removal, he often invokes the idea of a time machine. “My goal is to help people appreciate the scale of the problem, and put ‘solutions’ into context,” he says. 

Imagine all carbon removal technology as one big time machine, winding the clock back on emissions. If the world is emitting just under 40 billion metric tons of carbon dioxide in a year, how far back in time could this year’s total carbon removal take us? Right now, the answer is somewhere around 10 seconds. 

We eventually need to reach net-zero emissions if we’re going to avoid the worst effects of climate change. And it’s pretty clear that 10 seconds is a pretty far cry from being enough to zero out a year’s worth of emissions. There are two things we’d need to do for this time machine to be more effective: scale up carbon removal technology, and drastically scale back emissions. 

It’ll take time, and likely a lot of it, to get carbon removal technology to a point where it’s a more effective time machine. There are technical, logistical, and economic challenges to figure out. And early projects, like the Climeworks direct-air-capture plant in Iceland, are still getting their footing.

“It’s going to take many years to make significant progress, so we should start now,” Ho says. And while we figure all that out, it’s a good time to focus on decarbonization, he adds. Slashing our emissions is possible with tools we already have on the table. Doing so will make it a bit more feasible for carbon removal technologies to eventually play a significant role in cleaning up our emissions. 

If you’re curious to learn more, including how big a dent larger projects might make, check out David Ho’s article from earlier this year in Nature. You can also take a look back at some of our recent coverage of carbon removal below. 

Related reading

Carbon removal tech is vacuuming up significantly less than one-millionth of our fossil-fuel emissions. Get all the details in my latest story.

Startup Climeworks has been one of the major actors in putting direct air capture on the map. We put the company on our list of 15 businesses to watch in climate tech this year.

The US Department of Energy is committing big money to carbon removal. Earlier this year, the agency announced over $1 billion in funding for the technology, as my colleague James Temple covered.

Another thing

Around a decade ago, a huge wave of startups working on energy and climate-related technologies failed. This surge and crash in what’s often called cleantech 1.0 holds many lessons for innovators today. 

Now, as interest and funding in climate and energy technology companies again is surging, what should we take away from the previous generation of startups? My colleague David Rotman took a careful look for his latest story. Give it a read!

Keeping up with climate  

The University of California system is basically done with carbon offsets. While paying to balance out your own emissions sounds like a good deal, there are a host of problems with the practice. (MIT Technology Review)

Generating an image using AI can require as much energy as fully charging a smartphone. Smaller models doing other tasks (like generating text) can be significantly less energy intensive. (MIT Technology Review)

COP28 is in full swing. Here’s a quick roundup of a few of the headlines that have caught my eye so far. (If you need a catch-up on what’s happening at the UN climate talks and why fossil fuels are center stage, check out my story from last week here.

  • The head of the conference has been criticized for his comments about fossil fuels. (Vox)
  • Over 20 countries pledged to triple the world’s nuclear energy by 2050. (Canary Media)
  • Nations committed over $400 million in funding to help vulnerable nations pay for climate damages. These are the first pledges to the loss and damage fund, created at last year’s talks. (NPR)

A rule change in California slashed the value of rooftop solar panels six months ago. New sales are (predictably) down since the change. (Canary Media)

The Salton Sea is a salt lake in California. It contains a fascinating ecosystem, and apparently a whole lot of lithium. There might be 18 million metric tons of the metal under the main lake, the equivalent of nearly 400 million EV batteries. (LA Times

Congress set aside $7.5 billion for EV chargers. But there hasn’t been a single one installed with the money yet. (Politico