Melting ice: NSF-funded project will focus on Antarctic ice sheet and rising seas
As the air and the surrounding sea continue to warm, the West Antarctic Ice Sheet (WAIS) will ebb and recede. Its meltwater will cause ocean levels to rise around the world, eroding shorelines and inundating cities.
It’s a well-known narrative connected to global warming, but exactly how this scenario will unfold and what its precise impact will be is still a mystery.
Assistant Professor of Geological Sciences and Environmental Studies Molly Patterson and affiliated research associate Denise Kulhanek were awarded a $3.24 million National Science Foundation grant from its Office of Polar Programs to answer some of these questions.
“Simply put, the uncertainty is there because it is a complex system with feedbacks between different Earth system components operating on different time scales,” Patterson said. “This is why we have assembled a multi-disciplinary team that includes a glaciologist, geologists, oceanographers, a microbiologist, and ice sheet and climate modelers to work together and tackle these questions.”
Called Sensitivity of the West Antarctic Ice Sheet to 2°C (SWAIS 2C), the four-year project will run from 2022 to 2025 and was developed by international partners in 10 nations: the United States, New Zealand (the lead nation), Germany, South Korea, Japan, Italy, the United Kingdom, Spain, Australia, and the Netherlands. Binghamton, whose share of the award is $1.15 million, is the lead institution, and is joined by Columbia University, the University of Nebraska-Lincoln, Colgate University, Rice University, Northern Illinois University and Central Washington University.
Using a new drilling system specifically developed for the project, researchers will recover and analyze sediment cores from key locations along the West Antarctica Ice Sheet’s Siple Coast region, adjacent to the grounding zone at Kamb ice stream and the Crary ice rise.
The new paleoenvironmental data gleaned from sediment recovered beneath the ice sheet will help the researchers to better understand the influence of climate system dynamics and solid Earth processes on ice sheet sensitivity in a warmer world. Understanding how the ice sheet responded to changes in the past is key to improving the models that help scientists predict its likely response to future climate change and its contribution to rising sea levels.
That future isn’t far away.
“At the current rate of CO2 emissions, global mean temperatures will reach 1.5°C and 2°C above pre-industrial levels in 10 and 20 years, respectively,” Patterson said.
The West Antarctic Ice Sheet currently holds enough ice to raise global sea levels by 3 to 5 meters. It’s considered highly sensitive to future climate change, as much of the ice rests on bedrock thousands of meters below the sea level and is exposed to the warming Southern Ocean.
Satellite observations demonstrate that the WAIS is losing mass faster than other regions, but the lack of geological or paleoenvironmental records makes it difficult to predict how its future will unfold. The lack of data results from logistical difficulties in accessing these records and the financial costs required to conduct research in one of the most remote regions on Earth. However, the new drilling technologies developed for this project have tried to address some of these cost issues.
“Geological data are essential, as they provide the direct evidence on the extent of the ice during a given time period,” Patterson said. “This boundary condition is necessary to assess whether models are able to capture observed variability during warmer times in Earth’s history prior to making any assumptions about the future.”
A warming world
To account for the impact of global warming, scientists often compare global mean temperature to the pre-industrial period, before factories, automobiles and other innovations began sending excess carbon dioxide and other gases into the atmosphere.
With that in mind, the Earth also has gone through previous warm spells, called interglacial periods. Geological data from the last interglacial period (115,000 to 130,000 years ago) suggest that the global mean temperature peaked at 1°C higher than during the pre-industrial period, and average temperatures may have been as much as 2°C higher during an interglacial period between 395,000 to 425,000 years ago. The global mean sea level may have been 6 to 13 meters higher than the present day during such periods, and ice sheets in Greenland and the Western Antarctic were likely significantly smaller.
But the temperature increase we’re facing in future decades is much more extreme; based on current global emissions policies, it’s estimated that global mean temperatures will increase by 2.1°C to 3.9°C by the year 2100. The last time temperatures rose to this level was during the Pliocene epoch between 3 and 3.2 million years ago, Patterson pointed out.
Geological records from this period recovered from the Antarctic margin are sparse, but they suggest that the West Antarctic Ice Sheet and even the marine-based margins of the East Antarctic Ice Sheet were greatly reduced. Global sea level, however, may have swelled 7 to 18 meters higher during the Pliocene than today.
Patterson will head to Antarctica for fieldwork during the November 2023 to January 2024 field season, when the second drilling season at the Crary Ice Rise is expected to take place. The project will also deploy teams of scientists to attend science meetings following the field seasons at the University of Otago in New Zealand in order to carry-out initial analyses on the sediment cores before more detailed studies at homes institutions will occur.
As with all NSF-funded programs, there is also an educational component: Kulhanek will lead Antarctic School 3.0, a week-long program that introduces graduate and post-doctoral researchers to Antarctic sediment cores through lectures and hands-on activities. Currently an associate research scientist and staff scientist with Texas A&M University’s International Ocean Discovery Program, Kulhanek will start a position this fall as a full professor at Germany’s Christian-Albrechts-University of Kiel.
This is the third such program Kulhanek has run, and it is expected to be held at the Oregon State University Marine and Geology Repository, which houses cores collected by the U.S. Antarctic Program and other ice- and land-based drilling in Antarctica. The US NSF SWAIS 2C award has also secured funds to support an educational specialist, who will help develop educational materials and work with the project’s international partners.
Science is inherently a collaborative enterprise, especially with a project of this scope. Patterson is also excited about related research that Presidential Diversity post-doctoral researcher Adriane Lam is doing through the International Ocean Discovery Program, she said.
“We know the West Antarctic Ice Sheet is sensitive to what the oceans are doing, so the work Dr. Lam is doing is so extremely complimentary,” she said. “We are really starting to build a great program here in the Department of Geological Sciences and Environmental Studies that address some big-picture and timely questions that face earth scientists through two international science programs: The International Ocean Discovery Program and the SWAIS 2C Project.”