Decision-Making Under Uncertain Climate Change: A Response, and an Invitation, to Bret Stephens

By Robert Lempert and Marjolijn Haasnoot

In columnist Bret Stephens’ first blog post for the New York Times, published at the end of April, he highlights the uncertainty surrounding climate change, warns against overconfidence, and issues an invitation to dialogue. We agree that significant uncertainty exists regarding the future impacts of climate change and the costs of avoiding those impacts, that it is dangerous to ignore or downplay that uncertainty, and that acknowledging these uncertainties can provide a strong foundation for dialogue.

A vast literature exists on uncertainty and climate change. Most of it suggests that uncertainty is a reason for action. That said, it remains a significant challenge to determine what actions most effectively balance society’s many goals, in the presence of deep uncertainty about the likelihood of various futures and how our actions are related to consequences.

In exchanges with Stephens, both Andy Revkin and Costa Samaras highlighted the Society for Decision Making Under Deep Uncertainty as a community that brings together researchers and practitioners from all over the world. We develop, apply and exchange experiences on methods, approaches and case studies on decision making under deep uncertainty. Climate change is one of the policy domains (though not the only one) of great interest to many of the Society’s members.

To help decision makers, planners and investors make decisions in uncertainty, various methods and tools exists to identify typically robust or adaptive plans. For example, models are often used to explore the future and to stress-test investments or current policy (see the blog of Julie Rozenberg). This helps to identify contingency actions to keep the investment from failing or identify alternatives. By assessing the performance of various alternatives under multiple possible futures robust actions can be identified that perform well under many futures. As decisions are made over time, recent approaches consider dynamic adaptation over time by exploring development or adaptation pathways under multiple possible futures. This helps to identify short-term actions and future options to be implemented, depending on how the future unfolds.

Such analysis can also build consensus among parties to a decision with different interests, values, and expectations about the future. This has been demonstrated in many situations, including the Dutch Delta Programme (read more here and here), the Louisiana Master Plan for a Sustainable Coast the UK Thames Flood Barrier (read more here and here), and the Colorado River Basin Supply and Demand Study.

We invite Bret Stephens to explore the potential for such approaches to acknowledge uncertainty, avoid overconfidence, promote deliberation among diverse parties, and help craft consensus on sensible approaches to climate change.

We look forward to the conversation!

Robert Lempert and Marjolijn Haasnoot are members of the leadership team of the Society for Decision Making under Deep Uncertainty. Lempert is a principal researcher at the nonprofit RAND Corportation, and Haasnoot is an environmental scientist at Deltares and Delft University of Technology.