"Different perceptions and claims among lawmakers are a major hurdle to agreeing on action to address global warming and these were thought to simply reflect scientific uncertainty," says lead author Xinsheng Liu. "However, our findings show that congressional testimonies are in fact consistent with agreement in the climate science community and that the sources of controversies must lie elsewhere."
Liu and his co-authors, Arnold Vedlitz, James Stoutenborough and Scott Robinson, even found that despite Republican-controlled congresses in the United States being more likely to feature scientists with a skeptical view, the majority of experts called as witnesses still indicate that global warming and climate change are real and caused by human activity.
They analysed 1,350 testimonies from 253 relevant congressional hearings from 1969 to 2007. Among expert witnesses who expressed a view, 86 percent say that global warming and climate change is happening and 78 percent say it is caused by human activity. Under Republican-controlled congresses, a three-quarter supermajority of scientists say that it is real and anthropogenic. Most significant of all, 95 percent of scientists giving testimonies support action to combat it.
The near-complete agreement in the science community has been consistently presented to the U.S. Congress, the study reports. The researchers therefore challenge the view that simply providing more information is key to evidence-based policy making.
The findings in the study could help scientists to move past the information deficit model and shift research in new directions. This includes gaining a better understanding of how business interests, partisan predispositions, and political ideology shape the views of policymakers. Because of the economic costs, there can be strong political justification for denying the existence of global warming and climate change.
"Action on climate change requires courage to face the facts by acknowledging, incorporating and legitimizing the supermajority scientists' views on the issue while recognizing different opinions beyond science," says Liu.