A limited coalition begins sustained stratospheric aerosol injection
A coalition declares and sustains a multi-season injection program at scale sufficient to produce a measurable increase in stratospheric aerosol optical…
Claude · 2052–2062 · grey-swan
Prior state
Solar radiation management had remained confined to modelling and small field experiments, constrained by a soft international norm against deployment and by the absence of any state willing to accept the attribution liability. Meanwhile heat exposure in the Indo-Gangetic plain, the Gulf, and parts of Southeast Asia had reached levels at which outdoor labor becomes physiologically impossible for extended periods each year.
Material change
A coalition declares and sustains a multi-season injection program at scale sufficient to produce a measurable increase in stratospheric aerosol optical depth. The change is not primarily in the climate — the first-order temperature effect is modest — but in the international order: climate becomes a matter of direct interstate liability and unilateral physical action, and a governance instrument is negotiated after deployment rather than before it.
Why now
Two conditions converge in this decade. Heat exposure in the coalition's core territories reaches the point at which a lethal season produces a political decision rather than a study, and the delivery capability — sustained high-altitude dispersal at scale — reaches maturity roughly a decade after a state first funds it seriously, which the bridge assumes occurred in the 2040s. The decision itself is a political act taken after a specific catastrophic season, which is why it is a rupture rather than a threshold.
Mechanism and resistance
The counter-coalition responds with trade measures, litigation in whatever fora remain functional, and demands for compensation for attributed monsoon and rainfall changes. Attribution science becomes an intensely political discipline, because the difference between a bad monsoon and an injected monsoon cannot be established with the confidence that a liability claim would require. The termination-shock argument — that stopping abruptly would produce rapid warming — hardens into a strategic reality: once begun, the program is difficult to stop, which gives the coalition a durable form of leverage and gives its opponents a permanent grievance.
Consequences
Mitigation politics is destabilized in both directions, with some governments treating the program as license to relax decarbonization and others intensifying it precisely to shorten the program's necessary duration. Ozone and regional precipitation effects are contested throughout on evidence that never becomes conclusive. The most consequential outcome is precedential: a coalition of states that were not the historical emitters demonstrates the capacity to act physically on the shared atmosphere without the consent of those who were.
End state
A sustained injection program is operating, an international instrument regulating it has been negotiated under duress or has conspicuously failed to be, and interstate climate liability is a live legal and diplomatic question rather than a theoretical one.
Observable test
A declared, multi-season program with a measurable increase in stratospheric aerosol optical depth attributable to it; the presence or absence of a negotiated instrument; formal state claims for attributed damages.
Disconfirming sign
A non-use agreement holds through the interval and activity remains confined to modelling and small-scale field experiments.