After the 1.5 degree target

The climate conversation would be so different if we had a $10/100-year ton of CO2 removal

AI-slop courtesy of ImageFX.

The 1.5 degree target is dead. The focal point of target activism for much of the last decade died of anthropogenic causes this year, as global temperatures merrily zipped past what was meant to be an ultimate speed limit. Due to the convoluted way the UN keeps tracks of these things, the official death certificate won’t be issued for some time yet. But make no mistake about it: 1.5 has ceased to be, it’s kicked the bucket, shuffled off its mortal coil and joined the bleedin’ choir invisible.

It is an ex-target.

In stages-of-grief terms, most of climateworld is still in denial, but UN Secretary General Antonio Guterres has moved on to bargaining. In a recent speech to the UN Environment Program, he argued 1.5 is not dead, it’s resting: “scientists tell us that a temporary overshoot above 1.5 degrees is now inevitable…but this is no reason to surrender. It’s a reason to step up and speed up.”

Obviously, messaging around this is awkward. Any number of countries, states, municipalities and corporate boards publicly wedded themselves to the 1.5 goal over the last ten years, and walking away from all that was always bound to be tricky. Nobody wants to be stuck behind the podium announcing that the thing you ballyhooed as necessary just a few years ago is now impossible.

But if 1.5 degrees is an ex-target, what are we to replace it with?

Well, what do we want a target to do, anyway?

To my mind, the point of a target is to concentrate attention on the specific thing that will make the most difference. Targets exist to guide decisions. The point is to align climate action with the climate outcomes we want.

And the smart way to do that is to focus on costs.

Dollars and cents.

The one question that will make the biggest difference to our climate trajectory over the next seventy-five years is brutally simple: How much does it cost to take one ton of carbon dioxide out of the atmosphere?

Currently, we add about 40 billion tons of carbon dioxide to the atmosphere every year. Natural carbon sinks remove about 18 billion of those from the air. That leaves 22 billion tons of additional airborne carbon dioxide in the air each year.

When you get past the romantic nonsense, the real question is: how much are we willing to pay to bring that number down to zero?

Because there are thousands of ways of preventing emissions in the first place, and hundreds of ways of removing greenhouse gases from the air once they’re emitted.

But resources are limited.

Anytime you devote resources to less efficient ways of abating carbon dioxide, you’re leaving carbon dioxide in the air needlessly. If we were really focused on the climate first, we’d be much more cost conscious.

The $100/ton solutions often talked about as an aspirational target are still an order of magnitude too expensive to get us where we need to be. At $100 per ton, getting to net zero costs $2.2 trillion — more than twice the U.S. defense budget.

That’s a non-sense number: still an order of magnitude too high.

Instead, we should aim for a $10 ton of carbon dioxide removed from the atmosphere for at least a 100-years.

If we could do that, our climate problem would be pretty close to solved.

A $10/100-year ton would make net zero a $220 billion/year proposition. That sounds like a lot, but it really isn’t. We’re already spending five times that much on climate — more than a trillion dollars a year.

Of course, a $10/100-year ton feels out of reach. But that’s because carbon dioxide removal research has concentrated on approaches where costs are high and have no realistic prospect of falling.

The field is bifurcated between engineered approaches (i.e., big crazy machines) that cost $1,000+ a ton, or tree-planting projects that come in at $20-50 a ton, but only keep carbon out of the atmosphere for 20-40 years, and also compete for land with farmers.

In the middle you get a family of mineral-based techniques —enhanced rock weathering, ocean alkalinity enhancement— that are longer-lasting but more costly, coming in at around $50-$320 a ton.

That just means the tech we have is not up to the job.

Yet.

The usual objection to focusing on low-cost long-duration carbon dioxide removal invokes moral hazard. “If you create a get out of jail free card” people say “polluters are just going to keep polluting!”

This objection has it backwards. Our goal is not to punish people for insufficient green virtue; our goal is to bring down the concentration of atmospheric greenhouse gases. Developing high quality, low cost carbon removal technologies brings us much closer to that goal.

Take heavy-trucking, to take just one out of dozens of possible examples.

Electrifying big trucks requires big batteries, so decarbonizing heavy trucking is expensive. One study by Catalyst Climate suggests over the lifetime of a heavy truck, electrifying road haulage would stop a ton of carbon dioxide from being emitted at a cost of $50 per ton saved.

Say your decarbonization budget is $50. With that much money, you could take five times more carbon dioxide out of the atmosphere if you had a $10/100 year ton than by buying that fancy electric truck.

Imagine a world where we do have a $10/100 year ton of carbon removal. In that world, insisting on high-cost emissions reductions over low-cost carbon removals would mean up leaving a bunch of CO₂ in the atmosphere. Needlessly.

“Well, Quico would say that,” you’re thinking, “his job is all about developing low-cost 100-year CDR.” But that’s backwards too: I decided to work in this space because it’s the most important thing to do, not the other way around!

Today, the only family of approaches with a fighting chance to get to a $10/hundred-year ton rely on photosynthesis in the ocean. If we’re ever going to get the tech right, this is how we’re going to do it.

Some researchers think the way forward is macroalgae — kelp or sargassum are the ones most often mentioned. The people I work with tend to focus more on microalgae — the invisible kind of microscopic seaweed scientists call phytoplankton. Some researchers think phytoplankton carbon would work better in cold waters — the biggest research group in the field is targeting the Gulf of Alaska. The approach I’ve focused more on would happen in warmer waters in the Pacific. Who knows who’ll turn out to have been right?

The only way to find out who’s right is to try all these approaches in parallel: the kelp, the sargassum, the cold water phytoplankton, the warm water phytoplankton, all of it. If anything is going to yield a $10/100-year ton, it’s going to be in this space.

All hung up on the unburied corpse of the 1.5 degree target, Climateworld still hasn’t caught on that a $10/100-year ton of carbon removal is a live possibility.

When it does, the climate conversation is going to change. A lot.