2

Keynote Address: Overview of the Polar Regions

Richard Alley, Evan Pugh University Professor of Geoscience at Pennsylvania State University, provided a keynote address that centered the International Polar Year (IPY) 5 on people—especially students and early-career researchers (ECRs)—alongside advances in observation and modeling. He observed that hands-on polar research often builds skills that translate directly to societal applications, citing former students whose field techniques later supported aircraft safety diagnostics, disaster recovery, and engineering risk assessment. IPY activities, he suggested, can excite the public and future researchers alike. Alley addressed six themes that are detailed in this chapter.

SEA-LEVEL RISE AND ICE SHEET PROCESSES

Alley noted that large and highly visible coastal-protection proposals, for example, the “Ike Dike” for Houston, plans for New York, and initiatives around the San Francisco Bay Area, illustrate the scale of investments that hinge on credible sea-level projections; he mentioned cost estimates of billions of U.S. dollars to underscore the importance of accurate projections. He pointed to evidence that some sea-level rise estimates in major assessments may run low relative to supporting literature and historical outcomes, in part because several models simplify or omit processes that can accelerate ice loss (e.g., sub-ice-shelf melt, stress damage, calving at ice fronts). He described multimodel experiments under strong warming that span outcomes from Antarctic mass gain (lowering sea level) to multimeter rise, with model structure remaining a leading source of uncertainty (Seroussi et

al., 2024). In his view, an IPY-scale effort that combined field observations, remote sensing, laboratory work, theory, and data-assimilative modeling could improve parameterizations and narrow key uncertainties. Alley argued that if even a small fraction of anticipated protection costs, such as those outlined above, are directed to research, highly valuable information could be yielded.

OCEAN–ICE INTERACTIONS, CIRCULATION, AND SEA ICE

Alley described how evolving freshwater and mass fluxes from ice sheets—the time-varying ways in which ice sheets add freshwater and ice mass to the ocean—can alter atmosphere and ocean behavior, whereas many climate models historically treat ice sheets as noninteractive “white mountains” (Alley et al. 2015). Incorporating interactive ocean–ice processes, particularly those occurring beneath ice shelves, was presented as critical for developing more credible projections. He outlined potential Southern Ocean responses to increased freshwater, such as stronger surface stratification, productivity and nutrient effects, and sea-ice redistribution, noting that tilting density layers can steer warmer waters toward grounding zones, with implications for Antarctic Ice Sheet mass balance (Bronselaer et al. 2018). Alley then shifted to the North Atlantic region, describing Greenland freshwater input and a strengthening hydrologic cycle (Bamber et al., 2018), observing that public and policy maker understanding of these circulation risks can be uneven and that better quantification of freshwater fluxes and coupled effects would be useful.

Alley also discussed the role of sea ice in abrupt regional climate variability, pointing to past episodes where winter sea ice changes coincided with large temperature swings. As seasonal navigability expands, he suggested that increasing human activities lead to greater operational demands, including forecasts across time horizons (e.g., tactical through decadal), and a greater capacity for icebreaking support and rescue. Counterintuitively, as perennial sea ice retreats, total demand for icebreaking can rise as human activity increases, including increased transits through sea ice.

BIODIVERSITY, PERMAFROST, AND THE CARBON CYCLE

Alley pointed to recent research describing observations near Churchill Canada of bears constrained on land by delayed sea ice formation and increased risks of human encounters (Stroeve et al., 2024). He connected these interactions to broader Earth system concerns: paleoclimate records and recent studies that suggest that when greenhouse gases increase in the climate system, terrestrial greenhouse gas emissions (e.g., boreal forest fires, long-smoldering permafrost) contribute to increased atmospheric greenhouse gas concentrations, which can delay sea ice

formation (Canadell et al., 2021; Virkkala 2025). He suggested that reconciling model–paleoclimate differences would be valuable for projecting future change.

ECONOMICS AND VALUE OF INFORMATION

Alley discussed a commonly held viewpoint that warming yields net economic benefits in the Arctic. He noted that some economists may question whether these analyses fully account for disruption duration, losses of high-value assets, and spillovers from neighboring regions facing stress. IPY5 research that includes a robust Arctic economic assessment, he suggested, can clarify tradeoffs. More broadly, he argued that decision-quality polar information, such as observing, modeling, and forecasting outputs about polar processes and impacts (e.g., sea-level and coastal risk information, ocean–ice interaction and freshwater flux information, sea ice services), could deliver benefits that exceed program costs.

COMMUNICATION AND WORKFORCE

Alley emphasized engagement strategies that could align with potential IPY5 activities; for example, communication could be embedded in flagship efforts and paired with brief, well-supported opportunities for early-career voices (e.g., community-run observing projects, open-data dashboards, storytellers in residence). Everyday examples can ground the conversation for general audiences. One example is how GPS on cellular phones only works because engineers apply Einstein’s theory of relativity to correct the difference between how satellites’ clocks tick at different rates than clocks on Earth; another example is the way fundamental research underpins many life-saving medical technologies (e.g., transcatheter aortic valve replacement). Such examples can anchor conversations in the value of science before connecting audiences to polar research. This information can be carried by diverse messengers from science, local communities, and industry; universities and philanthropy can help stabilize student participation in the near term.

DISCUSSION

In response to questions, Alley proposed a two-track strategy: implement solutions that can be adjusted as projections change and invest in research to narrow those projections, acknowledging that ice-sheet behaviors driven by fracturing and calving cannot be predicted with high precision. He also spoke to sustaining student support through institutional and philanthropic partnerships to prioritize continuity of support for students and ECRs, particularly during funding uncertainty. Finally, he supported celebrating scientific advances without implying that challenges are resolved, again underscoring the value of multiple, trusted communicators.