David Roberts gives the obvious answer to those climate naysayers who employ negative arguments about the economic effects or say that there’s no point in the US doing anything if China won’t join in.
The U.S. must act because all people have a moral obligation to act. We have no guarantee that if we act, others will act; we have no guarantee that if everyone acts, it will be enough. But inaction is not a choice. If the danger were an invading army from another planet or a raging global pandemic, we wouldn’t be having these arguments. The need for everyone to act would be obvious. Quibbles over who acts first, or who benefits most from the planet not being invaded, or how to avoid spending “too much” to avoid being annihilated would rightly be seen as verging on sociopathic. Everyone would be eager to act, despite having no certainty of success, because the alternative is simply unacceptable.