Uncertainties run rampant throughout climate change. While scientific uncertainty receives the bulk of attention, uncertainty permeates the economic, social, and political realities of climate change. Some uncertainties are inherent, while others may be reduced through more research, new technologies, more careful language, or other strategies. Uncertainties complicate the identification of solutions and negotiation of agreements, at least in part because people use and manipulate uncertainties to support their interests. This presentation is part of a larger study that considers the many sources of uncertainties in climate change; their ethical, policy, and other implications; and how various players use and manage uncertainties in different situations. This presentation focuses on uncertainties in climate science, how climate scientists communicate uncertainties, how these strategies can affect climate policy, and how scientists can improve communicating uncertainties to support debate on important climate policy issues.

Uncertainties affect the ways people see problems and evaluate alternatives. Professionals face different problems in the face of uncertainty. Scientists must decide how to communicate uncertainties in their work and how to reduce uncertainties through additional research. Philosophers disagree about the right thing to do in a given context. Policy makers from the local to the international levels must assess the need for action and the merits of different policy options in the face of multiple uncertainties. Judges and lawyers are faced with decisions about assigning and allocating responsibility when causal links are extremely complex and causes are spatially and temporally distant from effects. Corporate and environmental advocates see different challenges and opportunities in the uncertainties. All interests use and manipulate uncertainties to support their interests, often relying upon uncertainty to cloak the values and interests that lie at the heart of debates over climate policy.

The portrayal and management of uncertainty implicate many ethical issues. For example, justice is a matter of fairness, of making sure that everyone gets what they are supposed to get. In order to evaluate their climate positions and vulnerabilities, people need to know what information is available, how variable or certain that information is, and how the certainty is likely to change over time.

The communication of uncertainties can affect public perceptions about climate science itself. Clear and detailed portrayals of uncertainties can improve perceptions of the salience of reports, to help people decide what information is relevant to the problem and can improve perceptions of credibility, of how good the science is. Better communication about uncertainties also can help readers to see reports as more legitimate, as fair and unbiased.

Policy makers can make better decisions about how to act in the face of uncertainty if they understand the nature of the uncertainties relating to various policy alternatives. They need to know which uncertainties are reducible and which are not and what it will take to reduce uncertainties. Climate scientists often are expected to produce work that is policy relevant without being policy prescriptive. The way that uncertainties are portrayed and disaggregated can affect the degree to which climate science provides useful information for debates about climate ethics and climate policy.

Climate science is extremely complex and uncertain. Researchers are accustomed to recognizing and describing uncertainties, and many do so in creative ways. Such strategies are essential but sometimes are inadequate to inform debates over issues such as who should be held responsible for climate change, who the winners and losers are likely to be, and other issues. Researchers could make their work even more relevant to decision makers and the general public by adopting additional strategies for disaggregating and communicating uncertainties. Such strategies can help to ground policy debates in science while allowing discussion to focus on the values and interests that often are the real center of concern.