It's not that international diplomacy won't matter, but individual countries are already taking action to reduce carbon emissions for various reasons beyond worries about climate change.
World leaders gathered at a United Nations summit this week to kick off 15 months of negotiations aimed at finalizing a climate pact next December in Paris. If you focus on those international climate talks, though, you'll miss most of the real action. The fate of global efforts to tackle climate change – and of the businesses that will win and lose as a result – depends far more on what countries do at home.
Climate change has long been approached as the ultimate foreign policy problem. Greenhouse gas emissions anywhere raise temperatures everywhere. What that means for climate policy is that emissions cuts anywhere curb global warming everywhere. Since cutting emissions usually costs money, it makes sense for each country to ask other countries to act while trying to do as little as possible themselves: that way, they keep their costs to a minimum, but still benefit from reduced climate change because of what others have done. The danger is that if every country adopts this attitude, no one will do much of anything. The only way out of this beggar-thy-neighbor quagmire, strategists have long assumed, is for countries to reach a legally binding pact in which they all curb greenhouse gas emissions at the same time.