With new evidence of global warming, how soon will people react?

Until recently, warnings from scientists about the risks of CO2 have largely been ignored. A century ago, the Swedish scientist Svante Arrhenius suggested a link between warming and industrial CO2 emissions. Now that the dangers are known, will people react quickly or, like frogs in water that warms gradually to a boil, will we find ourselves stuck in a scalding pot before it's too late? Facing global warming, are people like frogs?