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Removals required

Removals required

We’ll need a wider variety of ways to remove carbon from the atmosphere if we’re going to keep the planet cool.

Spoiler alert: cutting emissions isn’t going to be enough. The latest IPCC report highlights an “unavoidable” need to remove large amounts of carbon dioxide from the atmosphere in order to keep 1.5 degrees of warming in sight.

As much as 6 billion tons of carbon will need to be removed each year by 2050. That’s roughly equivalent to the annual emissions of the US. Even then there’s a risk that 1.5 is overshot, raising the possibility humans will need to find ways to “repair” and cool the climate by removing more greenhouse gases than they emit. Up to 17 billion tons may need to be removed every year by 2100.

Reforestation and afforestation are simple, cheap solutions. But as wildfires become more frequent, and available land more scarce, there is rising concern about tree planting as an effective, permanent strategy for storing carbon. This has spurred investor interest in a much wider variety of solutions that deliver negative emissions. 

First movers. Some of the world’s largest companies including Stripe, Alphabet, Meta, Shopify and McKinsey have made a $925 million commitment to buy offsets from early-stage startups that actually remove carbon from the air, as distinct from slowing or preventing emissions.

Frontier, which is owned by Stripe, is a first-of-its-kind attempt to accelerate the development of carbon capture methods that are unproven at scale. It will pool capital from corporates, governments and philanthropists and use it to purchase, years in advance, quantities of removed carbon from startups vetted by Stripe. This model, called an Advance Market Commitment (AMC), was piloted in the development of pneumococcal vaccines, and is touted as a way to catalyse an entire market for carbon removal within the decade. 

“If we were going to solve climate change with low-cost offsets we would have done it already,”  says Nan Ransohoff, head of climate at Stripe. “They just aren’t going to get us to that six gigaton number. If we want to have a portfolio of high-quality, low-cost solutions in the future we have no choice but to buy early-stage carbon removal now.”

What counts as a good removal? Frontier says it will employ a panel of experts to assess each pitch. To be in with a shot startups will have to prove:

  • Permanence: solutions that store carbon underground or in the ocean for more than 1000 years.
  • Footprint: burying captured carbon in areas that don’t impinge on arable land and have a low land area per ton of carbon removed.
  • Cost: $100 per ton or less, at scale.
  • Scale: a viable path to achieving 500 million tons per year.
  • Removal, not reduction: Stripe says it won’t buy at-source recapture of carbon (better known as CCS and often used by fossil fuel producers pumping CO2 back into oil and gas wells). “We see that as avoidance rather than removals and generally speaking there’s less of a customer shortage there because that kind of technology helps existing emitters reduce their emissions, which has value to them already.”

In terms of which solutions provide the best bang for buck, estimates vary greatly (although the UN’s Principles for Responsible Investment provides a useful guide). Perhaps the greatest unknown is whether Direct Air Capture – which strips CO2 from ambient air using chemical processes and stores the carbon underground – can achieve cost parity with natural solutions. If so, it could change the game.

Removal methods

Biochar. Charcoal produced from pyrolysis of biomass.

Afforestation and reforestation. Growing new and old forests.

Soil carbon sequestration. Increasing the organic carbon content of soils through land management.

Enhanced weathering. Use of carbonate and silicate rocks to accelerate geochemical processes on land and in oceans.

BECCS. Bioenergy combined with carbon capture and storage.

DACCS. Carbon captured direct from the air and stored.

Climeworks – a DAC company that recently received $650m in funding from investors including Swiss Re – has sold an initial 322.5 tons of carbon removals to Stripe at $755 per ton. Carlos Haertel, its chief technical officer, said he expects DAC to cost less than $500 a ton by the end of the decade and that it could come down to $150 by 2050. 

But he also outlined the uncertainties: the CO2 removal potential of DACCS (direct air capture and storage) is constrained by its high energy demand, large facility size, and availability of geological CO2 storage. Most operational facilities exist in places with sub-zero temperatures, so the equipment needs to be robust. Climeworks learnt that the hard way when its flagship “Orca” plant in Iceland temporarily froze this year.

Others are sceptical: “There is a role for DAC now to get the market going. It’s just that I don’t see it being a significant player in the end-game,” says Dr Shaun Fitzgerald, Director of the Centre for Climate Repair at Cambridge. Two nascent solutions that he has high hopes for include:

  • Artificial whale poo. This involves spreading a mix of nitrates, phosphates, and iron on the ocean surface in order to stimulate phytoplankton growth and trap carbon. “Regenerating the oceans with micronutrients is not available today as a carbon offset. But it will be – and it’s the only approach that gets you to tens of gigatons of carbon dioxide potential scale-up per year,” Fitzgerald says. 
  • Methane oxidation. Paint coatings containing photocatalysts could be applied to buildings. When methane in the air comes into contact with it in the presence of sunlight it will oxidise quickly and become CO2 – a far less potent greenhouse gas than methane. 

Before any of these are used for large-scale removals the priority has to be to cut emissions – but there also needs to be an acceptance that for certain industries that’s impossible and that removals will be needed. Stripe’s AMC will certainly trigger interest. But there’s another way to fire the starting gun on carbon removal: price carbon properly. Experts say a tax of $100 per ton would incentivise both removal and efficiency.

Tortoise Climate Summit

The world must cut emissions fast. At the second annual Climate Summit on 12 May, we will investigate whether a fair transition can help the world get to net zero faster. Do join us.


Green vs yellow vests
President Macron has been pushing his green credentials in a bid to woo the 7.7 million people who backed leftist Jean-Luc Mélenchon in the first round of the French elections. In a speech in pro-Mélenchon Marseille, he vowed to reduce air pollution, plant 140 million trees, fight for a European carbon tax and speed up greenhouse gas reductions. The uncomfortable reality is that the speed of emissions reductions has been lagging in France. In 2020, it was the only European country to miss its target on renewable energy production and in 2018 it postponed its energy reduction targets by five years. Le Pen is taking a decidedly different approach. She wants to champion a “non-punitive” approach to climate by pulling France out of the EU Green Deal, scrapping VAT on fuel and dismantling wind turbines that blight the paysage. The big question: will the gilets jaunes come back to haunt Macron on election day?


Crypto carbon
Since October nearly 20 million offsets – each equivalent to one tonne of carbon – have been turned into digital tokens, up from fewer than 200. The surge is driven by crypto traders seeking to capitalise on the rising price of nature-based offsets by bulk buying “junk” carbon credits that no one else wanted because they were either too old or unlikely to deliver the CO2 savings promised. Climate experts warn the FT that this could, in effect, lead to the laundering of offsets that don’t genuinely reduce or remove a tonne of carbon. Stay tuned to find out what happens when two of the world’s largest unregulated markets collide.


Hot water
Flooding in South Africa’s KwaZulu-Natal province has killed more than 443 people and left 40,000 without shelter. Most of the casualties occured in the city of Durban, large parts of which are still, ironically, without running water. “This disaster is part of climate change,” President Cyril Ramaphosa said as he visited communities affected by the flooding, “It is telling us that climate change is serious, it is here.” He’s right to make that attribution. Climate scientists this week concluded that the extreme rainfall in countries across the southeast African region is already more intense and damaging due to the climate crisis.

engagement and activism

Frying the planet
The price of sunflower oil has surged by over 200 per cent since the invasion of Ukraine, stoking fears among environmentalists of a return to a controversial alternative: palm oil. In response to the UK’s particular lack of cooking oil supplies (it imports 80 per cent of its sunflower oil from Ukraine), Waitrose has started rationing online purchases while Iceland has had to reverse its widely publicised ban on palm oil products. Malaysian producers have volunteered to step in to make up for shortfalls in the UK market, claiming their product is land-efficient and environmentally benign. But a recent study in Nature tells a different story. Satellite data shows that oil palm plantations have actually been expanding into carbon-rich forests in Malaysia and Indonesia, leading to large biomass losses.

Thanks for reading.

Barney Macintyre

Edited by Giles Whittell.

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