I'll partially answer this question, by pointing out
that this is a classic prisoner's dilemma issue.
Two members of a criminal gang are arrested and imprisoned. Each
prisoner is in solitary confinement with no means of communicating
with the other. The prosecutors lack sufficient evidence to convict
the pair on the principal charge. They hope to get both sentenced to a
year in prison on a lesser charge. Simultaneously, the prosecutors
offer each prisoner a bargain. Each prisoner is given the opportunity
either to: betray the other by testifying that the other committed the
crime, or to cooperate with the other by remaining silent. The offer
is:
- If A and B each betray the other, each of them serves 2 years in prison
- If A betrays B but B remains silent, A will be set free and B will serve 3 years in prison (and vice versa)
- If A and B both remain silent, both of them will only serve 1 year in prison (on the lesser charge)
In the prisoner's dilemma - in a single instance of the game and assuming no collaboration between the prisoners and assuming no other costs (ie. you're not going to be shamed for being a snitch), the best move is to betray the other.
- If the other has chosen to betray you, you get two years instead of three
- If the other has chosen not to betray you, you get zero years, instead of one.
However, in the long run (ie a series of repeated games), it makes sense that prisoners should cooperate, each opting for a series of one year sentences, rather than a series of two and three year sentences.
The scenario for climate change is the same.
Choosing to cooperate in solving the climate change has a cost for a given country (restrictions on their economic growth, unhappy business constituents), and there is also a reward (avoiding catastrophic climate change). The decision matrix for a single country looks like this:
| Rest of world coooperates | Rest of world doesn't cooperate|
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Cooperate | Pay economic cost | Pay economic cost |
| No catastrophe | Catastrophe |
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Don't cooperate | Don't pay economic cost | Don't pay economic cost |
| No catastrophe | Catastrophe |
The important thing to note here, is that the best outcome from the perspective of an individual country is that they don't cooperate on climate change, but the rest of the world does.
And it's worth mentioning, that it is the position of many countries in the world that they shouldn't have to pay the full economic cost. Typically the argument is that poorer countries like African nations and India have not yet developed their economies to the same extent that rich western nations have, and that a completely equal reduction emissions would stifle that development.
But the scenario where the whole world doesn't cooperate is much worse the scenario of paying the cooperate cost, and avoiding the catastrophe.
Individual countries can use this knowledge to leverage themselves a lesser obligation to climate change targets.
That is - an individual country knows that every other country values avoiding catastrophe more than the cost to pick up the slack of this individual country.
So you can have a situation where some countries are going to free ride on the cooperation of the other countries, in order to get this most beneficial position of avoiding catastrophe, as well as not paying the economic cost.
There are few things the other countries can do in response:
- Not cooperate themselves, in a technique called brinksmanship. Because this opens the possiblity of catastrophe, the original country may agree to start cooperating in order to avoid the the much worse alternative of catastrophe.
- Find other ways to punish the country for not cooperating. eg. exclude them from trade agreements.
- Suck the cost up.