As 1.5C overshoot looms, a high-level commission will ask: what next?

It seems increasingly unlikely that global temperature rises below 1.5C (the most difficult goal in the Paris Agreement) – which is the hardest goal – will be possible. “Well below 2C” is a stretch.

Yet there has been little discussion at an international level on how to handle “overshoot” of those goals. A high-powered commission will launch in May to break the silence.

Climate diplomats are assembling a 15-strong team of former presidents, ministers, representatives of international organisations, and other representatives to explore options on deep adaptation, carbon dioxide reduction (CDR), and geoengineering. Climate Home News can tell you.

The Climate Overshoot Commission will examine sensitive questions about ethics and feasibility of possible ways to reverse global warming that are not yet proven or problematic.

“The primary strategy to combat climate change should remain reducing greenhouse gas emissions, but it has also become necessary to explore additional strategies,” Jesse Reynolds, executive secretary of the commission, told Climate Home.

France’s Pascal Lamy, director general of the World Trade Organisation between 2005 and 2013, has been appointed as chair. He is the president of Paris Peace Forum which will host the commission.

Edward Parson, a professor of environmental law at the University of California, suggested the idea of a commission to evaluate climate engineering options in 2017.

Parson was one of 11 members of a steering committee made up of policymakers, academics, and politicians to help shape the future direction of the commission. Among them, five were from developing countries, including Cop27 host Egypt’s environment minister Yasmine Fouad, former Marshall Islands president Hilda Heine and Youba Sokona, vice-chair of the Intergovernmental Panel on Climate Change (IPCC).

Laurence Tubiana, Paris Agreement architect, and Janos Pasztor (executive director of Carnegie Climate Governance Initiative (C2G), were also members.

“How will the world manage the risk of temperature overshoot? That is the question that nobody is talking about,” Pasztor told Climate Home. “There isn’t enough attention paid to the magnitude of the risk for removing the huge amount of carbon dioxide that will keep us to 1.5C.”

The latest science suggests that overshoots of 1.5C or even 2C are highly probable.

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A Nature paper published last week shows that there is a 6–10% chance of reaching 1.5C without exceeding it, even assuming all climate commitments for 2030 and the mid-century.

The theory is that global temperatures can be lowered by sucking carbon out from the atmosphere through biological solutions, such as reforestation, and technological ones like direct aerial capture. However, tree planting can compete with food production for land. Carbon capture technology is also energy-hungry.

The latest report from the IPCC concluded sucking carbon dioxide from the air is “necessary” to achieve net zero emissions and “an essential element” to limit heating below 2C by the end of the century.

Although there is no substitute for urgent and deep emissions cuts, carbon dioxide removals can be used to offset residual emissions from difficult-to-abate industries like aviation, agriculture, and some industrial processes.

To limit global warming below 2C, five billion tonnes of CO2 must be removed annually by 2050. under one IPCC scenarioThe number could rise to 13bn by 2025. Any delay in cutting emissions will increase the dependence on climate stabilisation.

Temporary overshoots of climate goals are dangerous for human societies as well as ecosystems. “Many human and natural systems will face additional severe risks, compared to remaining below 1.5C,” the IPCC’s impact report warned. Some impacts, such as ice sheet and glacier melt and sea level rise, “will be irreversible”.

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Although CDR is present in all IPCC scenarios it is not yet clear if there are any plans to scale up the technology.

A joint initiative between the US, Canada, and Saudi Arabia aims for a global net reduction of 100 millions metric tons CO2 per annum by 2030. There are also efforts to support research in the USA and the UK and to develop methods to include carbon accounting in the EU.

Silicon Valley is joining the fray. Stripe, an online payment processing platform, launched a $925m fund earlier this month to purchase offsets from start ups that will permanently remove carbon dioxide from our atmosphere by 2030.

Stripe, Shopify, Meta, and McKinsey jointly finance the Frontier fund. It aims at signaling to investors and researchers that these technologies are in demand.

Climate scientist Zeke Hausfather, Stripe’s climate research lead, told Climate Home that understanding what removal technologies could work at scale and driving their cost down was necessary if they are to be used in decades to come.

Elsewhere, Venture capital firm Lowercarbon Capital launched a $350m fund in invest in carbon removal start-ups and Swiss carbon removal company Climeworks raised $650m from institutional investors earlier this month.

“But the private sector can only push things so far,” said Hausfather, suggesting governments help fund research and development of CDR approaches.

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At UN Climate Change negotiations, the issue was largely ignored.

For Oliver Geden, a lead author of the IPCC report on mitigation and senior fellow at the German Institute for International and Security Affairs, that’s unlikely to change “until there is an acceptance that overshooting 1.5C is unavoidable”.

While “not a magic bullet,” Geden said countries have already said yes to CDR by adopting net zero emissions targets – the “net” being achieved by balancing sources and sinks of emissions.

“I’m of that bottom-up view that countries have a net zero target should and can explore CDR,” he told Climate Home. The top-down alternative of sharing among nations the delivery of climate change removals brings about considerations that are both equitable and historic, which many wealthy countries want to avoid.

That conversation is uncomfortable for many climate campaigners, who are concerned that a focus on removals is at best a distraction from the need to phase out fossil fuels and roll out clean energy – and at worse a fig leaf for climate inaction.

“We urgently need the weight of global financing to invest in a radical overhaul of our polluting energy, food and industrial systems. But tech bros prefer to throw good money after bad into the carbon removal pipedream, letting polluters continue business-as-usual while appearing green,” Teresa Anderson, climate justice lead at Action Aid International, told Climate Home.

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For MJ Mace, a climate negotiator for the Alliance of Small Island States, there is “a real fear that the pressure comes off emissions reductions” if the issue of removals is pushed too forcefully in the public consciousness.

And yet, if emissions cuts are still lagging behind targets at the end of this decade, “we are going to end up having to rely on CDR on such a huge scale to meet these goals that we are not going to be able to pull it off” unless investment and planning start now, she said. “It’s such a dance.”

Solar radiation management, also known as geoengineering, is an even more sensitive subject than removing carbon from the atmosphere. Still largely in the realm of science fiction, the potential to block the sun’s warming effect by pumping aerosols into the high atmosphere is part of the commission’s mandate.

Pasztor said solar geoengineering is “unbelievably controversial” but leaders have to consider what risks they are willing to take to meet the 1.5C goal.

He heads the Carnegie Climate Governance Initiative (C2G), which is aiming to push a resolution about addressing overshoot risks at the UN general assembly by 2020.