New scientific review identifies Antarctic coastal blind spots limiting sea level projections

Three Colorado School of Mines researchers contributed to a new, international, community-led scientific review that warns that major gaps in knowledge along Antarctica’s coast are now one of the biggest obstacles to reliably predicting future global sea level rise. 

The paper, recently published in American Geophysical Union’s Reviews of Geophysics, synthesizes current understanding of how ice, ocean, atmosphere and the solid Earth interact in Antarctica’s coastal zone, and highlights key knowledge gaps and the need for improved observations at a pan-Antarctic scale. 

The review was written by 80 scientists across 17 countries, from across glaciology, oceanography, geophysics, and atmospheric science, coordinated through the Scientific Committee on Antarctic Research (SCAR) RINGS Action Group. RINGS is also endorsed by the Council of Managers of National Antarctic Programs (COMNAP), which ensures to provide logistics knowledge for efficient survey planning and better coordinate support when it is provided by national Antarctic pr

Ryan Venturelli

Among the co-authors are Mines’ Ryan Venturelli, a paleoglaciologist and assistant professor of Earth, space and planets; Matthew Siegfried, a glaciologist and associate professor of Earth, space and planets; and Hannah Verboncoeur PhD ‘26, a glaciologist who graduated this summer from the Mines Geophysics program. The paper brings together existing observations, models, and theory to highlight how incomplete data continue to limit estimates of Antarctic ice loss and future sea-level rise.  

“Antarctica’s grounding zone is the nexus of ice-ocean interaction and ultimately represents a flux gate for ice mass loss," Venturelli said. “It takes a great deal of international coordination to measure, map, and model this critical region of the Antarctic Ice Sheet.”  

A critical control point for sea level rise 

The Antarctic coastal zone is not simply the edge of the continent. It is a tightly coupled system where grounded ice meets the ocean, and where small changes can have outsized consequences. Processes occurring near the grounding zone—the point where ice lifts off the bed and begins to float—can regulate ice discharge or, under certain conditions, trigger feedbacks that accelerate ice loss. 

“Ice makes for a sensitive system when you consider its contact and interactions with the ground, ocean and atmosphere,” said Verboncoeur, now a senior climate resilience specialist at ICF. “Gaps in how well we can represent that coupling introduce uncertainty in how much ice Antarctica will lose to the ocean and how fast. Improving our constraints on these processes at the coastal zone of Antarctica is how we turn a wide range of possible futures into sea-level projections communities can plan around.” 

Observations over recent decades show that Antarctic mass loss has increased. The most rapid changes are driven by interactions between the ice and surrounding ocean, and by ice flow at the margins of the ice sheet, rather than surface melting alone. Yet key coastal conditions remain poorly mapped. 

The biggest gaps—and why they matter 

The review identifies persistent gaps in direct observations of coastal bed topography and sub-ice shelf cavities. Because ice sheet models are highly sensitive to conditions at the coast, even advanced models can produce misleading results when this data is missing or poorly constrained. 

Matthew Siegfried While satellite observations provide powerful measurements of ice motion and surface change, they cannot observe the bedrock under ice from space. 

As a researcher, Siegfried spent six weeks performing ground geophysical surveys to understand the coastal transition in Antarctica and three years later, another seven weeks performing more surveying and drilling through 800 meters (1/2 mile) of ice to investigate the shallow ocean column just off the coast.

“We have so rarely actually stepped foot on this key coastal margin of Antarctica. We can make inferences about what the coastline looks like and how it might behave from airborne or satellite data, but to truly map how these environments control ice flow, we need to directly access these remote and often rugged environments,” Siegfried said.

Venturelli spent the 2025-26 Antarctic research season as part of an on-ice team of 29 scientists, drillers, engineers and Antarctic field specialists attempting to drill for a 200-meter sediment core from the bedrock deep beneath 500 meters of ice at the Crary Ice Rise on the Ross Ice Shelf. Her work uses these geological samples from beneath Antarctica to estimate how the volume of the Antarctic ice sheet has changed through the last thousand to tens of thousands of years.

“I am excited for an improved modern perspective to compare against the reconstructions my research team creates using sediments and geochemistry to identify where the coastline was in the past,” she said.

A roadmap for coordinated action

Because no single nation can achieve comprehensive coverage alone, the authors emphasize that international coordination is essential.

“Uncoordinated surveys risk leaving gaps or duplicating effort. This paper provides an evidence-based framework to support coordinating RINGS activities under SCAR and COMNAP, helping to build more comprehensive datasets for improved sea-level projections”, said first author and the chair of the RINGS Action Group, Dr. Kenichi Matsuoka at the Norwegian Polar Institute.

“Such internationally coordinated efforts can serve as a steppingstone towards the next International Polar Year 2032–33”, Matsuoka concludes.

For the full list of contributing countries and institutions, visit the Norwegian Polar Institute website.