Plenaries
Time: Monday June 1, 2026 11:00 - 11:55 EDT
Title: The Art of Uncertainty: Planning for a Future that is Hard to Imagine
Speaker: Dr. David Spiegelhalter (University of Cambridge)
YouTube Recording: https://youtu.be/qQXqmVkOkIA
Abstract: In today's world of profound uncertainty—aptly described as the "conscious awareness of ignorance"—traditional decision-making frameworks often fall short. Where appropriate, we can assess and evaluate probabilities for well-defined events, rather than relying on ‘vague verbiage’ to communicate uncertainty. But when facing "deep" uncertainty, where we cannot even imagine all the possible futures, conventional methods requiring exhaustive lists of possibilities with assigned probabilities become impractical.
This talk explores some essential qualities for navigating our uncertain age. First, humility requires maintaining openness to unanticipated events. Second, imagination allows us to envision potential futures, particularly adverse scenarios. Finally, resilience enables recovery from unexpected shocks. Both individuals and organizations need physical and mental reserves rather than systems optimized solely for current conditions.
By cultivating imagination, humility, and resilience, we can better face an unpredictable future—not by eliminating uncertainty, but by developing the capacity to adapt and recover when the unexpected inevitably occurs.
Time: Tuesday June 2, 2026 11:00 - 11:55 EDT
Title: Is the Rate of Warming Accelerating? A Statistical Assessment from Global to Regional Scales
Speaker: Dr. Claudie Beaulieu (University of California Santa Cruz)
YouTube Recording: https://youtu.be/U3yumfqYbs4
Abstract: With record-breaking temperatures observed in 2023 and 2024, there is ongoing debate about whether the rate of global warming has accelerated since the 1970s. The observed warming rate reflects the superposition of anthropogenic forcings and natural variability, and an acceleration can only be detected if the change in trend is large enough relative to background climate variability. In this talk, I address this question from a statistical perspective using changepoint models specifically designed to objectively identify changes in the parameters of a statistical model. Analyzing global mean surface temperature time series over 1850--2024, we find limited evidence for a recent warming acceleration at the global level — in most datasets, no significant change in the rate of warming is detectable beyond the 1970s. However, regional surface temperature observations tell a more nuanced story, with emergence of warming accelerations and shifts from cooling or near-zero trend toward warming in several regions. We conclude by discussing potential physical causes behind these regional changes in the rate of warming.
Time: Wednesday June 3, 2026 11:00 - 11:55 EDT
Title: Navigating Uncertainty in the AI Era of Weather Forecasting
Speaker: Dr. Christopher Subich (Meteorological Research Division of Environment and Climate Change Canada (ECCC))
YouTube Recording: https://youtu.be/VPv_kO2mnTU
Abstract: The emergence of artificial intelligence in numerical weather prediction has fundamentally disrupted atmospheric science, promising rapid and even unprecedented gains in both computational efficiency and forecast accuracy. However, this revolution also presents challenges at nearly every stage of national weather centres' forecast production chains. Speaking from the perspective of medium-range global atmospheric forecasting, this plenary explores how the meteorological community and Environment and Climate Change Canada (ECCC) are navigating these uncharted waters across three distinct fronts: scientific, operational, and institutional.
Scientifically, we face the challenge of predicting a chaotic atmosphere using unexplainable models. Early AI systems learned to minimize error by "hedging their bets" and smoothing out extreme events. Researchers are now actively working to characterize and mitigate this structural uncertainty. We will explore how native ensemble generation, adjusted loss functions that target realism, and physically informed neural architectures like PARADIS force AI models to generate realistic forecasts that capture dangerous extremes.
Operationally, life-safety organizations cannot simply deploy "black boxes." We examine ECCC's pragmatic approach to safe AI adoption, utilizing spectral nudging to pilot traditional physics-based systems with AI guidance while retaining the essential, high-resolution, and physically consistent outputs that clients and the public depend upon.
Finally, we address the institutional and computational uncertainty looming over the field. AI inverts the traditional compute paradigm, shifting the "heavy lifting" from steady, CPU-based operational runs to massive, "bursty," GPU-heavy model training. As tech giants leverage immense capital to hyperscale their models, we will discuss the "resolution ratchet," the hard limits of historical training data, and the future of sovereign modelling in the AI era.
Time: Thursday June 4, 2026 11:00 - 11:55 EDT
Title: What We Don't Know, and Why It Matters
Speaker: Dr. Katharine Hayhoe (Global Chief Scientist of Nature United and a Distinguished Professor at Texas Tech University)
Abstract: Uncertainty is central to atmospheric and ocean science. From chaotic circulation systems to future climate projections, our disciplines are skilled at characterising these uncertainties and communicating the risks they represent.
Yet today, the most consequential uncertainties we face are not those embedded into the physics of the climate system. Rather, they are the uncertainties inherent to the human decisions and systems that are driving unprecedented change. What happens over this century depends critically on how quickly we reduce emissions, how sustainably we manage our resources, how we adapt to impacts already underway, and how societies respond to risk.
Drawing on insights from behavioral and cognitive science, Dr. Hayhoe will explore why information alone rarely drives action and what scientists can do to ensure our work more effectively informs decisions that ultimately determine our shared future. Navigating uncertainty, it turns out, is as much a human challenge as it is a scientific one.