Chilling Reality: An Unseen Factor Is Accelerating Antarctic Glacier Meltdown

Alarming Insight: Undetected Mechanism Speeds Up Melting of Antarctic Glaciers

Researchers from UC San Diego’s Scripps Institution of Oceanography have found that the flow of meltwater beneath glaciers in Antarctica contributes to a faster rate of ice loss, a phenomenon known as subglacial discharge. This newly identified factor could have considerable ramifications on projections for global sea-level rise, particularly under scenarios of continued high greenhouse gas emissions.

Simulation data indicate that by the year 2300, the flow of meltwater beneath Antarctic glaciers could heighten sea-level rise by 15%, signifying that this factor should be integrated into future predictive models.

The recently published Antarctic ice sheet modeling study posits that the accelerated loss of ice from Antarctic glaciers is due to the outflow of subglacial meltwater into the sea. According to model simulations, this effect is sufficiently impactful to contribute significantly to global sea-level rise in the context of high greenhouse gas emissions.

Current major sea-level rise projections, such as those by the Intergovernmental Panel on Climate Change (IPCC), have yet to incorporate the additional ice loss resulting from subglacial discharge from beneath Antarctic glaciers. If this element proves to be a crucial driver of total Antarctic ice sheet loss, existing forecasts could potentially underestimate the rate of global sea-level rise in the coming decades.

Implications for Coastal Settlements

Tyler Pelle, the lead author of the study and a postdoctoral researcher at Scripps, emphasized the importance of precise projections for sea-level rise for the wellbeing of coastal communities. Millions of residents in low-lying coastal regions rely on accurate data to prepare for future challenges.

The study, which was published in Science Advances on October 27 and funded by multiple organizations, employed a model to simulate the retreat of two East Antarctic glaciers—Denman and Scott—under various emissions scenarios until 2300. This model differed from previous ones in that it included the influence of subglacial meltwater flowing out to sea.

Model Forecasts and Conclusions

The research focused on the Denman and Scott glaciers, which together possess the potential to cause almost 1.5 meters (approximately 5 feet) of sea-level rise. Under a high emissions scenario, the model showed that subglacial discharge could elevate the sea-level contribution of these glaciers by 15.7%, rising from 19 millimeters to 22 millimeters by 2300.

Notably, the model discovered that subglacial discharge would result in these glaciers retreating into a continental trench more than two miles deep about 25 years sooner than without this factor. Once this retreat reaches a critical point, the glaciers’ contribution to sea-level rise would markedly accelerate.

Jamin Greenbaum, co-author of the study, noted that this research serves as an alert for the modeling community, emphasizing the necessity of incorporating subglacial discharge into future projections. The study also underscores the importance of mitigating greenhouse gas emissions.

Understanding the Mechanics of Subglacial Discharge

Subglacial meltwater is generated where ice meets the continental bedrock due to geothermal heat and friction. Previous studies have indicated its presence under several large Antarctic glaciers, including the Thwaites Glacier in West Antarctica. The discharge of this meltwater into the ocean is thought to expedite the melting of the glacier’s ice shelf, further contributing to sea-level rise.

Future Research and Modeling Challenges

The research team is now working to extend their model to the entire Antarctic ice sheet and is planning to submit a proposal for this broader study. Future versions of the model may incorporate dynamic responses of subglacial meltwater to other environmental factors, providing more accurate projections.

The research team, including Greenbaum, is also planning fieldwork in Antarctica, funded by NSF and NASA, to directly examine the impact of subglacial meltwater on both East and West Antarctic ice sheets.

Citation and Co-Authorship

The study, titled “Subglacial discharge accelerates future retreat of Denman and Scott Glaciers, East Antarctica,” was published on October 27, 2023, in Science Advances with a DOI of 10.1126/sciadv.adi9014. Apart from Tyler Pelle and Jamin Greenbaum, co-authors include Christine Dow from the University of Waterloo, Adrian Jenkins from Northumbria University, and Mathieu Morlighem from Dartmouth College.

Frequently Asked Questions (FAQs) about subglacial discharge

More about subglacial discharge

• UC San Diego’s Scripps Institution of Oceanography Study
• Intergovernmental Panel on Climate Change (IPCC) Sea-Level Rise Projections
• National Science Foundation (NSF) Funding
• NASA Climate Change and Sea-Level Rise Research
• East Antarctica’s Denman Glacier
• Scott Glacier Research
• IPCC Emission Scenarios
• The Cecil H. and Ida M. Green Foundation for Earth Sciences
• Mathieu Morlighem Publications
• Overview of Antarctic Ice Sheet Studies