Global warming or hot air? Democratic politicians say climate change is a grave threat to the US. Their Republican counterparts accuse them of alarmism over a non-issue. A close study of public opinion suggests that neither stance chimes with a majority of Americans. Voters are best described as worried but unwilling. They are more concerned about climate change than most Republican politicians; but they are less willing than Democrats to back potentially pricey measures to curb it. That creates a test for presidential candidates in 2016. Barry Rabe, who has done extensive analysis of opinion polls, says: “All the evidence suggests there is growing concern about this issue, but limited evidence that that translates to any groundswell of support for any particular policy, especially one that imposes costs.” Mr Rabe, a public policy professor at the University of Michigan, says the lack of a “pivot” from concern to action has created a paradox, which the eventual 2016 nominees will have to navigate in November’s general election. The Republicans’ candidate cannot afford to alienate swing voters by appearing insufficiently worried; the Democratic nominee, expected to be Hillary Clinton, cannot risk turning them off with overly aggressive solutions.