It’s helpful to understand game theory if you want to know why it's so difficult to reach an international deal to reduce climate emissions. Everyone will be better off if everyone does their part, but if one country gets away with doing nothing while the others reduce their emissions, that country would be the biggest winner of all, enjoying the benefits of averted catastrophe without any of the costs. That calculation could lead to a lot of countries bailing out. No one wants to be the sucker who cuts emissions but still doesn't prevent catastrophic climate change because no one else participated.
So making a deal and sticking to it will require countries to place a lot of trust in one another. And that trust has to be painstakingly built.
When the world’s richest countries say -- as they did at the 2009 climate talks in Copenhagen, Denmark -- that they will contribute $100 billion a year to a Green Climate Fund to help poorer countries reduce emissions and adapt to the effects of climate change, and then they don’t pay in, it erodes trust. And yet, that’s what has happened so far, as John Upton reported in Grist last week. Only $7.5 million has been contributed to the fund’s coffers so far. That’s partly because it's not fully operational yet; it's intended to be funded at $100 billion a year starting in 2020. But it's also because wealthy countries are simply loath to part with the cash.
And it's not even that much money we're talking about here. Upton noted that $100 billion pales in comparison to the $500 billion that the world’s developed countries spend each year on fossil fuel subsidies.
Here are some other points of comparison: