3. Climate Games

(a 100-year simulation for 6-12 players)

Game-Theory Concepts

Game theory: The science of strategy

Strategy: A plan that takes account of your affect on what other players will do. Strategic thinking.

Dominant strategy: A strategy that pays you the most no matter what strategies the other players choose.

Naïve strategy: One which assumes without evidence that your opponent will not act strategically.

Game: A situation calling for strategy.

Formal game: A set of rules defining all possible moves by each player and listing the payoffs from all strategy combinations.

Formal strategy: A plan for what move to make in every possible situation in a formal game.

Payoff table: A table listing the payoffs to each player for every combination of strategies by all players. Most useful for a two-person game.


Dixit & Nalebluff (2009) The Art of Strategy.

The best news article on Copenhagen and game theory

What's a Game?

If your actions have a strong influence on the actions of others, and that matters to you, you're playing a game. Grocery shopping is not a game. International climate policy is.

"We should lead, so they will follow," is a strategy in a game. It's just not a very clever strategy. "Let's pay those who don't coop-erate, so they will do something," is even less clever, but that's Kyoto's Clean Development Mechanism.

In zero-sum games, what I win, you lose, so cooperation is useless. Fortunately the climate game is not zero-sum, but it is still one of the most difficult games for arriving at a cooperative outcome. Fortunately, this type of game, a public-goods (PG) game as been studied for years. It's time that climate negotiators paid attention to what has been learned.

The Latest Climate-Game Research (April 26, 2010)

Climate is a public good. If I improve it, you will benefit. If you enjoy it, it does not reduce my enjoyment. Marketable goods don't work like that, and public goods are not marketable. They require cooperation, if we are to gain maximum benefit net of cost. But experiments show there will be little cooperation without an an agreement. ...>>

To help teach climate-game strategies, the GEP Center has produced a 100-year climate simulation game that can be played by from 6 to 10 players. A class can play it at the rate of one move per day, giving them time to learn (1) the need for cooperation, (2) the difficulty of achieving it without a self-enforcing treaty, and something about how to design such a treaty. ...

Cartels Are PG Games

The OPEC cartel is surprisingly like a climate agreement. OPEC's "public good" is a higher price of oil. But as with climate, it pays each member to cheat, unless they have an enforceable agreement. Fortunately, they mostly cheat. ...


A treaty can change the game. If it punishes those who shirk their commitment, countries will not want to join. But if most must join or it will not take effect, that provides a motive to join. ...


In the other experiment, which used 13 groups, the researchers explored how the presence of an animal altered players’ behaviour in a game known as the prisoner’s dilemma. In the version of this game played by the volunteers, all four members of each group had been “charged” with a crime. Individually, they could choose (without being able to talk to the others) either to snitch on their team-mates or to stand by them. Each individual’s decision affected the outcomes for the other three as well as for himself in a way that was explained in advance. The lightest putative sentence would be given to someone who chose to snitch while the other three did not; the heaviest penalty would be borne by a lone non-snitch. The second-best outcome came when all four decided not to snitch. And so on.

Having a dog around made volunteers 30% less likely to snitch than those who played without one. The moral, then: more dogs in offices and fewer in police stations.