Americans have mostly passed the stage of wondering whether global warming is for real. They're far from unanimous, though, in seeing the matter as one of immediate urgency. You can gather as much from the chart below, which draws on polling by the Chicago Council on Global Affairs and WorldPublicOpinion.org. The same poll offered different takes on the topic and asked adults to pick the one that best matches their own. Just 17 percent agreed that "Until we are sure that global warming is really a problem, we should not take any steps that would have economic costs." Thirty-seven percent said the matter does need to be addressed, "but its effects will be gradual, so we can deal with the problem gradually by taking steps that are low in cost." Forty-three percent said the issue is "serious and pressing" and requires action now, "even if this involves significant costs." Thus, fewer than half the respondents now support steps that would cost them a significant amount of money. Of course, some Americans are really, really worried about global warming. In a Gallup poll fielded last month, 10 percent said they believe that "human life will cease to exist on earth" within the next 50 years because of global warming. This includes the 3 percent who think humankind will be gone within 10 years. There is broader fear that "flooding and droughts will become more common" within 10 years (or have already begun to do so) due to global warming, with 41 percent subscribing to this view.