Public Awareness of the Scientific Consensus on Climate

Lawrence C Hamilton

doi:10.1177/2158244016676296

Abstract

Questions about climate change elicit some of the widest political divisions of any items on recent U.S. surveys. Severe polarization affects even basic questions about the reality of anthropogenic climate change (ACC), or whether most scientists agree that humans are changing the Earth’s climate. Statements about scientific consensus have been contentious among social scientists, with some arguing for consensus awareness as a “gateway cognition” that leads to greater public acceptance of ACC, but others characterizing consensus messaging (deliberate communication about the level of scientific agreement) as a counterproductive tactic that exacerbates polarization. A series of statewide surveys, with nationwide benchmarks, repeated questions about the reality of ACC and scientific consensus many times over 2010 to 2016. These data permit tests for change in beliefs and polarization. ACC and consensus beliefs have similar trends and individual background predictors. Both rose gradually by about 10 points over 2010 to 2016, showing no abrupt shifts that might correspond to events such as scientific reports, leadership statements, or weather. Growing awareness of the scientific consensus, whether from deliberate messaging or the cumulative impact of many studies and publicly engaged scientists, provides the most plausible explanation for this rise in both series. In state-level data, the gap between liberal and conservative views on the reality of ACC did not widen over this period, whereas the liberal–conservative gap regarding existence of a scientific consensus narrowed.

Highlights

Studies by thousands of scientists have established that human activities are changing the Earth’s climate, principally through raising the concentration of radiatively active gases in the atmosphere
Direct surveys of scientists find levels of agreement on the reality of anthropogenic climate change (ACC) ranging from 87% among American Association for the Advancement of Science members generally, to 93% among working PhD Earth scientists (Pew Research Center, 2015) or 97% among active climate research scientists (Anderegg, Prall, Harold, & Schneider, 2010; Doran & Zimmerman, 2009)
The observation that acceptance of ACC and consensus both increased is compatible with the proposition that implicitly or explicitly communicating evidence of agreement among scientists encourages public acceptance of ACC itself

Summary

Introduction

Studies by thousands of scientists have established that human activities are changing the Earth’s climate, principally through raising the concentration of radiatively active (greenhouse) gases in the atmosphere. A second question with parallel wording (consensus) asks whether respondents think most scientists agree that climate change is happening caused mainly by human activities This question appeared on 11 of the New Hampshire surveys. The visual similarity between climate and consensus beliefs is striking, and its implication of substantial overlap is true Of those who think that climate change is happening caused mainly by human activities, 85% (New Hampshire) or 86% (United States) think that most scientists agree on this point. Age Female Education Ideology Education × Ideology Year Estimation sample F statistic Count R2 Adjusted count R2

NH Consensus

Findings

Discussion

Conclusion