 Imagine NASA is launching a new space mission. TV reporters are at the launch site. They talk about the technical challenges of launching a rocket, the physics of space travel, and the science of our solar system. Then to provide some balanced coverage, they also interview someone who thinks the moon landing was a hoax. Doesn't make sense, right? Typically, journalists try to give both sides of an issue equal voice to give balanced coverage of the issue. This is appropriate with social and political issues or matters of opinion, but does it work with scientific facts? Should media coverage of the facts surrounding a NASA space mission include the opinion that the moon landing was a hoax? Similarly, should someone who denies a scientific consensus on climate change be given equal weight with the 97% of climate scientists who agree with the evidence that humans are causing global warming? In these cases, giving equal weight to people who deny a scientific consensus is not providing balanced media coverage because it doesn't accurately reflect the science. Instead, it allows a small vocal minority to have their views amplified. Media coverage of climate science plays a big role in people's views about climate change. It's especially important because many people get their scientific information from mainstream media, from TV, from the radio, from the newspaper, from media sources on the internet. So for people who manufactured out about climate change, mainstream media provide useful tools in increasing misconceptions about climate change. They often achieve this by exploiting the journalistic norm of balance. To give another example, this is like insisting that an astrophysicist should share the stage with someone who believes the earth is flat. It conveys a misleading impression of ongoing scientific disagreement. What effect does this type of mixed media coverage have? One study tested this by showing two types of TV coverage about climate change. One version was a new segment showing a mainstream scientist explaining climate change. The other was the same new segment, but it also included someone who denied the human influence on climate change. What was the result? Among the group who watched the media coverage with just the mainstream scientists, 48% thought that most scientists agree that global warming was happening. Now, 48% is already disturbingly low, but among the group who watched mixed media coverage that included the dissenting scientists, perceived consensus was even lower. Only 36% thought that the scientists agreed. Mixed media coverage also lowered acceptance that climate change was happening and it lowered support for climate action. I've conducted similar research, but rather than show TV coverage, I showed a written article that gave climate scientists equal weight with scientists who reject their consensus. The left bar here shows what people think the consensus is if they're not showing any media coverage about climate change. The right bar shows perceived consensus after they're shown some mixed media coverage. So this essentially shows before and after. What it shows is just reading an article that gives scientists and contrarians equal weight lowers perception of consensus. People end up thinking that there's less scientific agreement after seeing mixed media coverage. This means that how the media cover various dimensions of climate science has a big effect on people's perception of these issues. Giving contrarians equal weight with climate scientists serves to misinform the public and reduce recognition that the climate is changing. Ironically, the journalistic standard originally designed to prevent bias actually leads to the systematic distortion of the science. With this in mind, how has media covered climate change over the years? Well, it doesn't look good. One study looked at media coverage from 1988 to 2002 in the Prestige Press, the leading newspapers in the US. They found that over half of the news reports on climate change gave contrarian views equal weight with climate scientists. This type of skewed media coverage has contributed to a false perception of a divided scientific community. There are some indications that things are improving. A follow-up study found that from 2003 to 2006, US Prestige Press coverage improved to the point where in 2006, nearly 97% of the coverage was accurate. That's not too bad in reflection of the 97% consensus in the climate science community. However, network television in the US is still disappointing with nearly 70% of news segments giving equal weight to opposing science. So portraying climate change as an equal debate between opposing science only serves to confuse people and lower public perception of consensus. What do we do about this? In my own research, I found two approaches that neutralize the misinforming influence of mixed media coverage. Firstly, explain how mixed media coverage can give a misleading impression. When I explained to participants about the strategy of trying to portray the false impression of ongoing scientific disagreement before showing them the mixed media coverage, I found that the misinformation was completely neutralized. Secondly, there's an even more powerful approach. Simply communicate the level of scientific agreement. When you communicate the simple message that 97% of climate scientists agree on human cause global warming, mixed media coverage has no effect. It enables people to realize that when they see two people arguing in the media, one side represents 97% of climate scientists and the other represents the 3% of scientists who reject the consensus. In short, more context helps people more accurately understand dimensions of climate change.