New Study of Antarctica's Thwaites Glacier Urges Reevaluation of Sea Level Rise Projections

A groundbreaking study led by glaciologists from the University of California, Irvine (UCI) has uncovered critical evidence of warm seawater intrusion beneath the Thwaites Glacier in West Antarctica.

Using high-resolution satellite radar data, the research team found that this phenomenon, occurring many kilometers beneath the grounded ice, is causing substantial melting and could necessitate a reassessment of global sea level rise projections.

Published in the Proceedings of the National Academy of Sciences, the study utilized data from Finland's ICEYE commercial satellite mission. The ICEYE satellites, which orbit the poles, use interferometer synthetic aperture radar (InSAR) to continuously monitor changes on Earth's surface. This technology provided a detailed time series of daily observations, closely aligned with tidal cycles, showing the rise, fall, and bending of the Thwaites Glacier.

"These ICEYE data provided a long-time series of daily observations closely conforming to tidal cycles," said lead author Eric Rignot, UC Irvine professor of Earth system science. "In the past, we had some sporadically available data, and with just those few observations it was hard to figure out what was happening. When we have a continuous time series and compare that with the tidal cycle, we see the seawater coming in at high tide and receding and sometimes going farther up underneath the glacier and getting trapped. Thanks to ICEYE, we're beginning to witness this tidal dynamic for the first time."

The study demonstrated that seawater intrusion, combined with freshwater generated by geothermal flux and friction, builds up beneath the glacier, creating pressure that can elevate the ice sheet. This process involves seawater with a lower freezing point due to its salinity, which contributes to the "vigorous melting" of the basal ice.

"Thwaites is the most unstable place in the Antarctic and contains the equivalent of 60 centimeters of sea level rise," noted co-author Christine Dow, professor at the University of Waterloo in Ontario, Canada. "The worry is that we are underestimating the speed at which the glacier is changing, which could be devastating for coastal communities worldwide."

The research team, including Enrico Ciraci, Bernd Scheuchl, and Valentyn Tolpekin, received financial support from NASA and the National Science Foundation. The study's findings underscore the urgency of addressing climate change and its impacts on polar ice regions, advocating for a renewed focus on reducing carbon emissions and improving predictive models.