The other climate crisis

As Earth warms, regional climate signals are accumulating. Some signals, for example, land warming more than the ocean and the Arctic warming the most, were expected and successfully predicted. Underlying this success was the application of physical laws under the assumption that large and small spatial scales are well separated. This established what we call the standard approach, climate science’s dominant paradigm. With additional warming, however, discrepancies between real-world signals and expectations based on this standard approach are piling up, especially at regional scales. At the same time, disruptive computational approaches are advancing new paradigms. Philosophers of science characterize situations where accumulating discrepancies (anomalies) and disruptions lead to a loss of confidence in the dominant paradigm as a ‘crisis’. Here we articulate what we consider to be the dominant paradigm, or standard approach, and the discrepancies and disruptions that have emerged in recent years. The policy implications of a purported crisis are discussed, as well as paths forward, crisis or no crisis. These paths include using signals to test assumptions and processes driving a warming Earth for the first time, developing testable hypotheses, and revitalizing conceptual thinking by filling gaps across climate-system components and spatial scales.