Arrow's shadow over climate governance

For thirty years, climate negotiations have failed to produce a stable and widely accepted rule for distributing mitigation burdens, even as finance, technology, and loss and damage have advanced. Political will, free-riding, and domestic constraints explain part of that, but not why the deadlock persists. This paper contends that the challenge is structural. It uses Arrow's voting paradox to diagnose the burden-sharing track of the climate negotiations and to draw the institutional consequences. Burden-sharing constitutes a preference-aggregation problem involving incompatible fairness principles. Arrow's impossibility theorem elucidates both the nature and direction of this difficulty: no procedure can transform divergent rankings of historical responsibility, capability, and equal per capita claims into a single, stable, and broadly accepted formula. Although the theorem does not establish formal impossibility within a treaty context or explain any specific negotiation breakdown, it highlights a constraint that neither improved analysis nor increased commitment has overcome. Because the constraint is structural and unsolvable, agreement proceeds by working around the aggregation problem. Issue linkage relaxes Arrow’s independence condition, while the Paris Agreement shifts aggregation from an ex ante distribution to self-differentiation, focal points, and an ex post stocktake of collective progress. Sen’s comparative justice helps explain why this works: parties need not agree on a fair allocation to agree that some outcomes are worse than others. The deeper threat to cooperation is therefore not disagreement over shares within the shared frame, but rejection of the frame itself. Burden-sharing deadlock is structural; attempts to revive a single master equity formula are likely to reproduce pre-Paris impasses.Paris avoids a negotiated ex ante allocation formula: self-differentiated nationally determined contributions and temperature goals coordinate action while leaving fair shares contested.Negotiators can use issue linkage, including climate finance and technology support, to make otherwise unacceptable mitigation packages viable.The global stocktake should assess collective adequacy without becoming an adjudicator of national fair shares.When the shared objective or participation itself is contested, priority should shift from refining burden shares to sustaining the common framework. Burden-sharing deadlock is structural; attempts to revive a single master equity formula are likely to reproduce pre-Paris impasses. Paris avoids a negotiated ex ante allocation formula: self-differentiated nationally determined contributions and temperature goals coordinate action while leaving fair shares contested. Negotiators can use issue linkage, including climate finance and technology support, to make otherwise unacceptable mitigation packages viable. The global stocktake should assess collective adequacy without becoming an adjudicator of national fair shares. When the shared objective or participation itself is contested, priority should shift from refining burden shares to sustaining the common framework.