The Guardian this week published my latest story about direct air capture of CO2, a topic that has fascinated me since the late 2000s. My 2012 Amazon Kindle Single, Suck It Up: How capturing carbon from the air can help solve the climate crisis, chronicled the very beginnings of the air capture story;  since then, startups working on harvesting CO2 from the sky have made tangible progress, as this story indicates. Here’s how it begins:

In Squamish, British Columbia, a Canadian town halfway between Vancouver and Whistler where the ocean meets the mountains, a startup led by Harvard physicist David Keith – and funded in part by Bill Gates – is building an industrial plant to capture carbon dioxide from the air.

Carbon Engineering aims to eventually build enough plants to suck many millions of tons of CO2 out of the air to reduce climate change. Its technology could help capture dispersed emissions – that is, emissions from cars, trucks, ships, planes or farm equipment – or even to roll back atmospheric concentrations of CO2.

The Calgary-based company is one of a crop of startups placing bold bets on technology designed to directly capture CO2 from the air. Lately, at least three have shown signs of progress. New York City-based Global Thermostat, which is led by CEO Graciela Chichilnisky and Peter Eisenberger, a Columbia University professor and former researcher for Exxon and Bell Labs, tells me it has recently received an infusion of capital from an as-yet-unnamed US energy company. As part of a demonstration project financed by Audi, Swiss-based Climeworks in April captured CO2 from the air and supplied it to a German firm called Sunfire, which then recycled it into a zero-carbon diesel fuel.

These companies are a long, long way from success, it must be said. Deploying direct air capture at a scale sufficient to make a difference to the climate would be a vast and costly undertaking. But their work matters because of the increasing likelihood that we will need to deploy “negative emissions” technologies like direct-air capture to avoid pushing through the 2 degrees of global warming that governments have agreed is a safe upper limit. This isn’t as well understood as it should be, in my view.

Climate science is ridiculously complicated and, as a non-scientist, I’ve struggled to make sense of the conflicting claims about how dire our situation is likely to become. Some people tell me that environmentalists and climate scientists are alarmists, exaggerating the dangers we face and squelching dissent. Matt Ridley, a writer whose work I admire, makes that argument in this excellent, in-depth podcast. Others say just the opposite, that scientists and economists feel pressure to underplay the seriousness of the problem, for fear of leading people to despair and inaction. Oliver Geden, head of research at the German Institute for International and Security Affairs, made this argument recently in the journal Nature, writing: “The climate policy mantra – that time is running out for 2C but we can still make it if we act now – is scientific nonsense.” Esquire magazine, of all places, published a long and powerful story last week under this headline:

When the End of Human Civilization Is Your Day Job

Among many climate scientists, gloom has set in. Things are worse than we think, but they can’t really talk about it.

It’s an unsettling read.

Here, meantime, is how David Roberts put it in an excellent analysis at Vox:

The obvious truth about global warming is this: barring miracles, humanity is in for some awful shit.

The fundamental problem is that the world’s biggest GHG emitters — China, the US,  Germany, the UK and India — are unlikely to stop burning fossil fuels anytime soon for a whole bunch of reasons, including, in the case of India, the fact that hundreds of millions of its poor people don’t have access to electricity. As Roberts puts it:

Holding temperature down under 2°C — the widely agreed upon target — would require an utterly unprecedented level of global mobilization and coordination, sustained over decades. There’s no sign of that happening, or reason to think it’s plausible anytime soon.

No matter what happens this winter in Paris.

Last year, in a report that deserved more attention than it got, the Intergovernmental Panel on Climate Change said that avoiding the goal of 2 °C of global warming will likely require the global deployment of technologies to remove carbon dioxide from the air.(For more about the need for carbon removal, here’s a good story from Brad Plumer at Vox.) Such technologies don’t exist today, at meaningful scale.

This is why direct air capture matters.