Signals and noise. Mass-media coverage of climate change in the USA and the UK.

How the mass media cover scientific subjects matters in many ways, whether scientists like it or not. Stem cells, genetically modified organisms, cloning, the environmental or health implications of chemicals or climate change: whatever the subject, media coverage has helped to shape public perception and, through it, affected how science is translated into policy, most notably in regard to the environment, new technologies and risks (Weingart et al, 2000). Conversely, political, economic and other interests have long tried to influence media coverage of particular topics to affect the public’s understanding and perception, and scientists are now becoming more aware of the power of the media. Consequently, the intersection of mass media, science and policy is a particularly dynamic arena of communication, in which all sides have high stakes. The integral role played by the media is not surprising, as it is still the main source of information and opinion for millions of readers and viewers—and voters—through newspapers, magazines, television, radio and the internet. As people gain most of their political, economic or other news from the media, so they do with scientific stories. Various studies have shown that the public gathers much of its knowledge about science from the mass media (Wilson, 1995), with television and daily newspapers being the primary sources of information (Project for Excellence in Journalism, 2006; NSF, 2004). Given their wide reach, it is therefore important to investigate the media’s coverage of scientific topics and how it influences both science and policy. In this viewpoint, we survey the media’s portrayal of climate science and man-made climate change—dubbed ‘global warming’, or anthropogenic climate change—and its coverage in the USA and UK as an important example of how science, politics and the media intersect and interact. More specifically, we explore how external influences and internal factors shape and define media coverage of climate science.