The main obstacle to adopting an effective global-warming policy in the United States is not, contra Neil deGrasse Tyson et al., skepticism about scientific claims. Rather, the main obstacle to our adopting an effective global-warming policy is that the warming globe has upon it China, India, etc. Global warming is a global issue, and even radical cuts in the U.S. emissions would have little practical effect in the absence of similarly serious commitments in the rest of the world.