Who owns the overshoot

Eighteen percent by 2030. Forty-five percent by 2035. Those are the global emissions cuts the UN Environment Programme now says are required even for the gentlest possible overshoot of 1.5C — a scenario in which the planet still warms to roughly 1.7-1.8C around mid-century before, provided removals scale and emissions fall, declining again by 2100. Current national pledges, fully implemented, deliver 5-8% by 2030 and 11-15% by 2035. That is the gap. It is not rhetorical. It is arithmetic.

The UNEP report released this week is titled, with uncharacteristic bluntness for the genre, 'The point of return.' Its central claim is that a temporary breach of 1.5C is now 'imminent and unavoidable,' and that the task has shifted from prevention to management: minimise the peak, shorten the duration, build a credible path back down. If current policies hold, the trajectory lands near 2.8C by century's end. If every submitted pledge is honoured, 2.6C. Both numbers describe a different planet than the one the Paris Agreement was negotiated to preserve.

So the question my column asks today is narrower than the headline figure. If overshoot is locked in, who owns the gap between the target and the trajectory? Because the gap is not an abstraction. It has a physics (more removals, faster cuts), an economics (someone pays, someone is paid), and a politics (someone decides). And the politics, this week, moved in exactly the wrong direction in the one jurisdiction that still has the institutional machinery to matter at the margin.

In Brussels, the centre-right bloc in the European Parliament is pushing to delay the EU's methane rules by three years and, more consequentially, to delay or scrap outright the second phase of the Emissions Trading System — the carbon price scheduled to cover transport and heating fuels. ETS2, as it is known in the files, covers roughly 40% of the bloc's greenhouse gas emissions. Italy and Poland pressed the same case at the European Council last week. The argument offered is industrial competitiveness; the effect, if the campaign succeeds, is to remove the single largest new price signal the EU had designed to carry the household and transport sectors through the 2030s.

Name the tradeoff plainly. ETS2 was constructed as a speed instrument — a carbon price is faster than regulation and cheaper, per tonne abated, than subsidy. Its weakness, which its opponents are now exploiting, is distributional: a price on heating oil and petrol lands hardest on households that cannot afford to switch heat pumps or electric vehicles on the compliance timeline. The honest version of the current fight would be a debate about the Social Climate Fund and how much of the ETS2 revenue is redistributed, to whom, and how fast. The dishonest version — the one in motion — is to kill the price and keep the target, and let the gap grow quietly.

This is where the UNEP arithmetic bites. Every five years of delay, the report calculates, adds roughly 0.1C to peak warming. A three-year delay on methane rules is not symbolic; methane is where the fastest, cheapest temperature reductions available this decade are hiding. A delay to ETS2 is not a pause; it is a decision to transfer the abatement burden onto instruments that do not exist yet, in a legislature that is visibly losing appetite for building them.

My reading is that the European centre-right has made a calculated bet: that the political cost of visible carbon prices on households exceeds the political cost of a widening emissions gap, because the gap is diffuse and the prices are concrete. The bet may be correct electorally. It is incorrect physically. Those are two different accounting systems and only one of them negotiates.

The comparison across regions sharpens the point. In the United States, preliminary figures suggest emissions rose in 2025, and the federal government has stepped back from the architecture entirely. In China, the national carbon market has now processed over a billion tonnes of cumulative trading volume and covers roughly 65% of the country's CO2 emissions — a system that was derided in its early years as a paper exercise and which is now, slowly, becoming a lever. The direction of travel in Beijing is toward wider sectoral coverage; the direction in Brussels, this month, is toward narrower. That reversal, if it holds, is the most important political fact in climate policy this year, more important than the UNEP headline, because it tells you which jurisdictions are preparing to manage the overshoot and which are preparing to be managed by it.

The Gulf is a separate problem again. There, decarbonisation is a question of what to do with revenue from a resource whose long-run price curve is now bending; the local calculus is about diversification speed, not about carbon prices on households that mostly do not pay for electricity at marginal cost. The Caucasus and Central Asia face a third problem: methane leakage from ageing fossil infrastructure, where the cheapest tonnes of global abatement sit, and where the capital to capture them does not. The single global frame flattens all of this. The gap is global; the ownership of the gap is not.

Which returns the question to Brussels. If ETS2 is delayed or scrapped, the EU's own 2030 target becomes a document rather than a trajectory. The Commission will still publish it. Member states will still cite it. But the instrument that was supposed to carry the second half of the decade will be absent, and the gap between the European pledge and the European outcome will begin to resemble the gap UNEP has just documented at the global level — a space in which everyone agrees the number and no one owns the delta.

The honest sentence, which the current debate is working hard to avoid, is this: an overshoot that is 'minimised' requires the instruments that are being dismantled. You cannot delay the price and keep the target and call the arithmetic unchanged. The UNEP report assumes removals scale, pledges are honoured, and the political machinery to deliver both continues to function. This week in Brussels, one of those assumptions came under direct attack from inside the building that is supposed to defend it.

The overshoot is now a given. Its depth and duration are not. Those are still decisions, taken by named people in named rooms, on named files, this autumn. The gap has an address. It is worth writing it down.