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 often framed as a problem of technology, politics, or individual responsibility. These all matter — but none can deliver global emissions reductions at scale on their own.
The reason is structural: the costs of reducing emissions are borne locally, while the benefits are shared globally. As a result, countries have limited incentives to act unless others do the same.
This makes climate change fundamentally a problem of cooperation. And in practice, cooperation requires reciprocity and common commitments. Without them, agreements remain fragile, and progress stalls.
In simple terms, climate action must take the form of a conditional commitment: I will if you will.
The Themis Mechanism is a proposal designed specifically to address this constraint. It departs from existing approaches by replacing largely voluntary commitments with structured reciprocity and common commitments. Its aim is to align national self-interest with global outcomes, so that cooperation becomes stable and self-reinforcing rather than voluntary and uncertain.
It has nothing to do with altruism. Instead, it creates conditions in which countries can pursue their own interests through cooperation — because reciprocity and common commitments make that the rational choice.
The remainder of this page contains links exploring the Themis Mechanism:
- four descriptions, ranging from a brief one-pager to a more in-depth document
- other resources, including an interactive Themis elicitation process page and ethical foundations
- recent Themis talks
Themis Mechanism descriptions
- The Themis Manifesto (1 page)
The idea in its shortest form. Start here if you are new to this. - Escaping the Trap: A Proposal for Policy Makers (2 pages)
The political case for Themis — why conditional commitments change the calculus for governments. - Escaping the Trap: An Urgent Alternative to 30 Years of Inadequacy (2 pages)
The case for Themis for a policy and media audience. We have treated climate change as a scientific and technological challenge. 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: Technical Proposal (8 pages)
The long form treatment: the mechanism, the elicitation procedure for determining the carbon price, and the analysis of fairness and incentives. For those who want a more complere argument.
Other Themis resources
- Interactive Themis Mechanism price elicitation page.
- 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. Including discussion and comparison to the UN’s existing framework of “common but differentiated responsibilities” (CBDR). Open for signatures.
Recent Themis talks
Talk: Climate Change Cooperation: the Themis Mechanism, Tübingen April 15th 2026.
Talk: Climate Change Cooperation: the Themis Mechanism, Copenhagen April 22th 2026, slides.