It Ain't Just the Heat, It's the Humanity: Evidence and Implications of a Knowledge-Based Consensus on Climate Change

Abstract:

Multiple lines of evidence have established the existence of an overwhelming scientific consensus on anthropogenic climate change. Despite this consensus, the public perception of expert agreement falls well short of reality. This "consensus gap", and experiments demonstrating that consensus invocation has significant impacts on public perception, have led to calls for increased consensus messaging. In order to facilitate such messaging, scientists and communicators must feel confident in invoking the consensus, and the public needs to find it credible. Of primary concern is that consensus is not a guarantor of correctness. While the existence of consensus is not itself evidence of a position's truth, it has been argued that scientific consensus can be taken as evidence that a given position is true if it is "knowledge-based" rather than arising from epistemic (mis)fortune or deliberate non-cognitive agreement. Here, we demonstrate that the scientific consensus on anthropogenic climate change is knowledge-based, satisfying criteria of social calibration, apparent consilience of evidence, and social diversity. We further discuss implications of a knowledge-based consensus for messaging, public beliefs, and policy support.