So the tipping point was social. That thought — a wrong one I hope — came to mind in the aftermath of a US election that set back prospects for reducing greenhouse gas emissions before major ecosystem or physical tipping points are reached. Such a setback has always seemed possible, but its sudden arrival took me by surprise.
Except that in this instance, public opinion has not reversed. Figure 1 combines data from 4 US surveys and 26 quarterly New Hampshire surveys that asked the same climate question from 2010 to August 2016, with highly replicable results. Over this period, the proportion who think that climate change is happening now, caused mainly by human activities, drifted upwards by about 10 points: from the low 50s to well over 60 percent. The pace has been glacial, still this seemed grounds for mild optimism. But how does this upward drift in public acceptance square with the drastic shift to rejection in Washington?
The rightmost data point in Figure 1 above is the Polar, Environment, and Science (POLES) survey conducted by the University of New Hampshire Survey Center in August 2016. Conducting telephone interviews during a presidential campaign, our August survey also asked respondents who they would vote for, if the election were held today. Figure 2 breaks down climate-change responses by voter preference. Only 33 percent of the Trump supporters, compared with 61 to 86 percent of other groups including nonvoters, agreed that human activities are changing the climate.
The POLES survey had a two-stage design, with its second stage just after the election. Both stages asked mostly the same questions. In the pre-election survey 63.4 percent of respondents thought that humans are changing the climate; after the election 64.5 percent thought so, a nonsignificant rise.
The post-election survey asked respondents who, if anyone, they voted for. Their choices included a new option for people who said they voted for other offices but not for president. (Survey researchers well know that self-reports of intentions or voting are not the same as actual voting, but they nevertheless provide useful proxies.) Figure 3 shows the climate-change breakdown. Twenty-five percent of self-reported Trump voters, compared with 68 to 99 percent of all other groups, agreed that humans are changing the climate. (The “no president” group is small, so their high percentage should not be over-interpreted.) However, the broad pattern of Figures 2 and 3 appears robust: in their views on climate change, Trump supporters stand far apart not only from Clinton supporters, but also from people who voted for other candidates, left the presidential choice blank, did not vote, or declined to say. Each of these groups differs significantly from Trump supporters, although not necessarily from each other.
Roughly similar patterns occurred with other climate-related or science questions on the surveys, including the physical facts of CO2 buildup or Arctic sea ice decline, whether scientists adjust their findings to get the results they want, whether science agencies such as NASA can be trusted for climate information, and whether renewable energy rather than more drilling should be a US priority. Figure 4 contrasts Trump-voter percentages with those for all other voter groups combined (post-election results shown; the pre-election survey found this pattern too). As usual, partisan divisions are widest on climate change.
The science and environmental views of Trump and Clinton supporters align roughly with their candidates; that result is not surprising. A less obvious result is that people who did not vote for either Trump or Clinton — because they chose a different candidate or did not vote at all — are generally closer to Clinton than to Trump in their science/environment views. The non-voters tend also to be younger, so consequences from policies associated with these views, such as slowing down or speeding up climate change, could play a larger role in their lives.