Overall there has been a modest increase in the percentage of Americans who believe that the effects of global
warming “have already begun to happen” since 1997, from 48 percent to 61 percent. However, this upward
trend masks very divergent trends among those identifying with the two major parties. While the percentage of
Democrats believing that global warming is already happening has increased substantially from
46 to 76 percent, the percentage of Republicans holding this belief has declined from 47 to 41 percent!
Global Warming Has Already Begun010203040506070801997 Nov 6-92001 Mar 5-72002 Mar 4-72003 Mar 3-52004 Mar 8-112005 Mar 7-102006 Mar 13-162007 Mar 11-142008 Mar 6-9%Republican Independent DemocraticA clue to the sources of this rather dramatic divergence in the views of Republicans and Democrats
concerning whether global warming is already occurring is shown in the next set of trend data on reactions to
news coverage of global warming. When asked their views about news coverage of global warming in 1997, 31
percent of Americans responded that they felt news of global warming was “generally exaggerated,” a figure that
increased to only 35 percent in 2008. But again, this very slight overall increase masks major differences between
Republicans and Democrats. While there has been a sizable increase in the percentage of Republicans believing
news of global warming is generally exaggerated, from 34 to 59 percent, there has been a slight decline in the
percentage of Democrats expressing this belief, from 23 to 18 percent.