numbers, not adjectives — D. J. C. MacKay
Climate Change Cooperation
April 21, 2026
In the long history of humankind, those who learned to
collaborate and improvise most effectively have prevailed.
— after Charles Darwin
The Themis Mechanism
Climate change is widely thought of as intractable. It isn’t. It is a collective action problem and we know how to solve those.
Decades of agreements have failed not because of lack of concern, but because of the structure of the problem. When the costs of acting fall on whoever acts while the benefits are shared by everyone, unilateral ambition achieves little. No amount of goodwill fixes that.
The fix is cooperation based on reciprocal commitments: I will if you will. Nations don’t need to sacrifice their own interests – they need a framework in which self-interest and the collective good are aligned. This is not idealism. It is how trade agreements, alliances, and every functioning collective arrangement works. We simply haven’t applied it to our climate crisis.
The Themis Mechanism is a concrete proposal for exactly that. Simple in structure, grounded in self-interest, designed to make cooperation the rational choice for every nation on earth.
Themis builds on a simple ethical principle: all people share equal rights and responsibilities to our atmosphere.
Themis Descriptions
The Themis Manifesto (1 page)
The argument in its shortest form. Start here if you are new to this.
Escaping the Trap: A Proposal for Policy Makers
The political case for Themis — why conditional commitments change the calculus for governments.
Escaping the Trap: An Urgent Alternative to 30 Years of Inadequacy
The case for Themis for a policy and media audience. We have treated climate change as a scientific and technological challenge – and the science and technology have delivered. The missing piece isn’t the science or the engineering. It’s in understanding ourselves: how humans cooperate, how incentives work, how to design agreements that make honesty the rational choice. Cooperation is not an idealistic aspiration – it is a practical human capability, one we exercise constantly in other domains. Themis applies it to climate.
The Themis Mechanism: Full Technical Proposal
The full formal treatment: the mechanism, the democratic procedure for determining the carbon price, and the analysis of fairness and incentives. For those who want the full argument.
The Equitable Atmosphere Declaration
A four-sentence statement of principle: that all people share equal rights and responsibilities to our atmosphere, and that failing to price its use is a root cause of climate change. Deliberately simple — the UN’s existing framework of “common but differentiated responsibilities” (CBDR) has proven so open to interpretation that it has stalled implementation for thirty years. Open for signatures.
Themis Resources
Interactive Themis Mechanism price elicitation page.
Talk: Climate Change Cooperation: the Themis Mechanism, Tübingen April 15th 2026.
Talk: Climate Change Cooperation: the Themis Mechanism, Copenhagen April 22th 2026, slides.