I'll admit, I haven't been feeling great this past month about our species' chance of surviving climate change. The deal nations agreed to at the COP26 climate summit, even if they all adhere to their promises, is probably only good enough to limit global warming to 2.1°C, according to Climate Action Tracker. And right now it's not looking like the U.S., currently the world's second-biggest carbon emitter, is going to come close to meeting its goals.
With Republicans refusing to come to the table, the Democratic Congress was pinning all its hopes for climate action on the Build Back Better Act, which Joe Manchin just killed (or at the very least, severely wounded). Last week's Weekly Planet newsletter from The Atlantic responded to the news by declaring, "Manchin has virtually sealed the planet’s fate: The world is all but guaranteed to warm by more than 1.5 degrees Celsius above its preindustrial temperature by 2040." Author Robinson Meyer commented, "I try to avoid despair when writing about climate change....But sometimes despair is the right emotion."
But right or wrong, despair isn't an emotion I can live with for very long. So instead, for this first blog entry of the new year, I'm focusing on the stories I've heard in the past few months that give me reason for hope. These five stories cover new and little-known developments that have the potential to avert, or at least mitigate, the coming climate catastrophe. Each one of them, on its own, could be a big piece of the solution to the climate puzzle; all five, taken together, could mean our species actually has a fighting chance of coming out of this crisis intact.
Game Changer #1: Carbicrete
When people think about what causes carbon emissions, they tend to picture cars and cows, not concrete. Yet this ubiquitous building material is responsible for roughly 8 percent of the world's carbon emissions — much more than aviation fuel (2.5 percent) and not that much less than agriculture (12 percent). If it were a country, it would have the third-largest carbon footprint in the world, right behind China and the U.S.
The main source of these emissions lies in the process used to make cement. It involves heating limestone and clay in a kiln to a temperature of more than 1,400 °C. Not only does this require huge amounts of energy, it also releases carbon trapped in the limestone — about 600 kg of carbon for every ton of cement.
But there's actually a way to cut this step out of concrete production entirely. A new Canadian product called Carbicrete replaces the concrete in traditional cement with steel slag, a waste product from steel production. Then — stay with me here — the mixture of steel slag, aggregate, and water is injected with CO2 and subjected to a chemical process that converts the CO2 to stable calcium carbonate, creating a strong, dense material. In other words, this material actually removes CO2 from the atmosphere, rather than creating more. About 150 kg per ton, in fact, plus the 600 kg that aren't produced from the cement.
Moreover, Carbicrete is stronger than traditional concrete and less susceptible to damage from freezing and thawing. And the material costs of its production are actually 10 to 20 percent lower than traditional concrete's.
So what's the downside? Well, there are two. First, the carbon curing process requires a factory, which takes money to build. And second, there's not enough steel slag available to make enough Carbicrete to meet all the world's current concrete needs. It could only replace about 10 to 20 percent of existing concrete. But 20 percent of 8 percent of all the world's carbon emissions is still 1.6 percent, which ain't hay.
Game Changer #2: Soil Carbon Storage
Remember how I said that agriculture is responsible for 12 percent of global carbon emissions? A lot of that has to do with the way we till the soil. Soil contains a lot of plant matter, and the carbon in that plant matter breaks down slowly over time. But when you take a plow to that soil, you expose more of it to the atmosphere, causing it to break down faster and release a lot of that stored carbon in the form of CO2. Since humans started farming roughly 12,000 years ago, we've released about 110 billion metric tons of carbon into the air this way.
But this trend is reversible. Farmers can put carbon back into the soil by planting deep-rooted perennial crops that store more carbon in the soil. They can grow cover crops to draw in carbon after the main crops are harvested and plow them under before planting to put that extra carbon into the soil. These techniques not only draw down carbon, they make the soil more productive, so we can grow more food on the same amount of land.
With the right techniques, even severely degraded soil can be restored. I read this year of a multi-year project that's just starting to regenerate the Sinai peninsula this way, creating a huge carbon sink and potentially improving rainfall across the Middle East. China has already done it on a large scale in the Loess Plateau, raising more than 2.5 million people out of poverty in the process.
Restoring degraded soil, one study says, could capture 1 to 3 billion tons of carbon each year. That's the equivalent of 3.5 to 11 billion tons of CO2 emissions — 11 to 34 percent of annual emissions from fossil fuel burning. Now that really ain't hay.
Game Changer 3: Ocean Farming
Agriculture has the potential to draw down carbon not just on land, but in the ocean as well.
Last summer, Freakonomics talked about this in an interview with kelp farmer Bren Smith. He's the author of Eat Like a Fish and the founder of Greenwave, a nonprofit aiming to get at least 10,000 growers started farming 1 million acres (about 4,046 square kilometers) of ocean. And since the kelp goes down a lot farther below the ocean surface than most crops go up from the ground, that's a very, very large volume of kelp.
Smith wants to make kelp the new soy. Not that many people eat straight-up soybeans and soy-based foods like tofu, but soy is in just about everything — not just food but also oils, lubricants, and plastics. Likewise, Smith wants to see kelp used not just in hipster salads, but in animal feed, fertilizer, bioplastics, and packaging materials. All of which would be net carbon negative.
And the benefits don't stop there. Seaweed also absorbs nitrogen and phosphorus that can cause fish-killing algae blooms. It battles the ocean acidification caused as the seas absorb CO2 directly. And it's a way to grow tons of food without taking up vast tracts of land (or, in this case, sea). Smith grows scallops, oysters, and mussels, as well as kelp, all on the same batch of long lines trailing down into the ocean.
Sadly, the Sierra Club claims kelp can't directly make a big dent in global carbon emissions — even if you sink the kelp to capture the carbon permanently, rather than harvesting and eating it. One square kilometer of kelp can sequester 1,000 metric tons of CO2 per year, which sounds like a lot. But when humanity is currently emitting the equivalent of 50 billion tons per year, it's a mere drop in the ocean.
Still, aquaculture does have the potential to be a carbon-neutral form of agriculture that could take the place of more carbon-intensive farming. It could also help mitigate the carbon emissions from other areas of agriculture, like cattle farming, as cows that eat seaweed emit far less methane. And it could do the same with other industries that produce carbon-intensive products that could be made from seaweed instead, such as fuel and fertilizer.
Game Changer 4: Enhanced Weathering
Here's another way to stuff more carbon into the oceans: enhanced mineral weathering. The ocean already absorbs quite a lot of carbon through natural weathering, which works like this:
- CO2 dissolves in rainwater.
- The slightly acidic rain reacts with carbon-containing rocks like limestone.
- The dissolved carbonates from the rock get carried to the sea and eventually settle on the seafloor.
- Over time, the layers of sediment build up and turn into rock.
Now, this doesn't seem like a net benefit, since the carbon started out trapped in rock and ended up trapped in rock. But as the carbonates from the rock enter seawater, they increase its alkalinity. That makes the ocean capable of absorbing more CO2 from the atmosphere.
Enhanced weathering speeds up this process by grinding rock up fine to expose more of its surface area, so rain dissolves more of the minerals in it. You can spread the ground-up rock directly in the ocean or, better yet, on cropland, where it boosts soil nutrients and increases crop yields. It can also improve crop health, fend off pests and disease, and fight soil erosion. And that ground-up rock reduces the need for petroleum-based fertilizers, so it's a two-fer.
Game Changer 5: Fusion
There's an old joke about nuclear fusion: It's a cheap, clean power source that's just 50 years away from becoming a reality...and always will be.
Except now it's not. This year, scientists at MIT successfully used a superconducting magnet to create a magnetic field strong enough to contain a fusion reaction. Having proved that is possible, they're now at work building SPARC, a working fusion reactor. And if that works, they'll get right to work on a bigger reactor, ARC, that can actually produce electricity. Clean, continuous electricity with essentially no fuel cost. If all goes well, it could be online by early 2030.
This is the true moon shot. Unlike the other game changers I've listed here, this is a technology that doesn't exist yet. It may take longer than expected to make it work, or it may not work at all. But the scientists behind it say they have "high confidence" that it will, making this cheap, clean, carbon-free power source could a reality in as little as eight years.
And SPARC may not even be the world's first fusion reactor. Another team made up of scientists from seven nations is already at work on ITER, a fusion power plant that's scheduled to fire up for the first time in 2025. It won't produce electricity either, but it can potentially be used to produce tritium, a necessary fuel for future reactors that do. China has fusion projects of its own in the works; yesterday one of them managed to keep a reaction going for a record 17 minutes. And a British company, Tokamak Energy, announced its own breakthrough in magnetic field generation last month.
Yes, I know there are other carbon-neutral energy sources that aren't in the experimental phase, that exist right here and right now. Solar, wind, hydro, biomass, and conventional nuclear fission all have a role to play in the decarbonization of the grid. And we'll surely need to scale them all up a lot over the next few years to have a chance of staying below 1.5°C.
But fusion, once we get it working, is essentially limitless. It means human society can continue to grow, continue to use ever more energy, and maybe not make our planet uninhabitable in the process. It may be too late to save us — but it definitely won't be too little.
For me, stories like these are a big help. They make me feel like my so-far feeble efforts to fight climate change aren't a waste of time. It's hard to keep banging your head against the brick wall that is Congress when it seems like it's already too late to do any good. But when I hear about new advances like these, I can believe that maybe, with their help, there's still time. And that gives me the will to sign in to one more Zoom meeting, write one more letter, attend one more lobbying session, and keep chipping away, bit by bit, at that brick wall.
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