Overshooting 1.5 °C: the ice won't give change

According to Reporterre, two reports published jointly on 2 November by the International Cryosphere Climate Initiative (ICCI) and the United Nations Environment Programme (UNEP) sound the alarm: temporarily exceeding 1.5 °C of warming could cause irreversible damage to the planet's ice. The two documents are titled "Overshoot and the Cryosphere: Averting Global Meltdown" and "State of the Cryosphere 2026".

That is all we know, Reporterre's summary stopping there. We have here neither the detailed figures, nor the melting timetables, nor the most exposed regions. Better to say so than to embroider. The rest of this article is our reading, not the content of the reports.

The idea of a "temporary overshoot" rests on a convenient bet: you cross the threshold today, and claw it back tomorrow, thanks to carbon-removal technologies that remain largely hypothetical. The warning restates a physical truth: ice is not a bank account. What melts does not come back because the temperature curve has since come down. The thermometer's "temporary" becomes the glacier's "permanent".

One can read this as a manifestation of what Marx called the metabolic rift, the break in the exchange between human societies and nature, widened by a system that demands ever more flows of energy and matter. In the contemporary version of the idea, summed up in the conceptual notes of La Gazette, accumulation offloads its costs onto ecosystems and onto the populations who have emitted the least. Overshoot is an almost pure form of this: the bill is deferred, and passed on to others, later.

Who are they? The inhabitants of valleys that depend on glacier water, residents of coasts threatened by rising seas, the peoples of polar regions whose territory is the ice itself. Not all have the same means to adapt. A dyke, a substitute irrigation system, a relocation: adaptation is expensive, and it is distributed according to wealth. Emissions, by contrast, have owners: fossil-fuel producers, industries, large investors. The discourse of "we are all responsible" dilutes them with great elegance.

If one takes the science seriously, the political conclusion is uncomfortable. An overshoot said to be "managed" presupposes carbon markets, offsets and technological bets, which is to say, finance. Avoiding overshoot presupposes planning the phase-out of fossil fuels, deciding what is produced, and for whom, and ending the subsidies that prolong the problem. This is called public planning, and it is precisely what the current order knows least how to do.

The ICCI and UNEP reports tell us what the ice will suffer. What remains is the question the ice does not ask: who among us will have the means to protect themselves from it?