Antarctic Ice Shelves Experiencing Significant Shifts Due to Intense El Nino Events, According to Latest Research

In a groundbreaking study published in the journal "Nature Geoscience" on January 8, 2023, researchers led by Fernando Paolo, a postdoctoral scholar at NASA's Jet Propulsion Laboratory, have explored the impact of El Niño and La Niña events on Antarctic ice shelves.

The study, which was funded by NASA and the NASA Earth and Space Science Fellowship, used satellite observations of the height of the ice shelves from 1994 to 2017. The findings suggest that changes in mass, rather than height, control how the ice shelves and associated glaciers flow into the ocean.

During strong El Niño events, ice shelves in the Amundsen Sea sector of West Antarctica gain mass at the surface but melt from below, losing up to five times more ice from basal melting than they gain from increased snowfall. Conversely, during strong La Niña events, the mass gain from snowfall exceeds mass loss by basal melting in ice shelves of the Amundsen Sea sector.

The intense 1997-98 El Niño increased the height of these ice shelves by more than 25 centimeters (10 inches). However, over the entire 23-year observation period, the ice shelves in the Amundsen Sea sector had their height reduced by 20 centimeters (8 inches) a year, for a total of 5 meters (16 feet), mostly due to ocean melting.

The opposing effects of El Niño on ice shelves - adding mass from snowfall but taking it away through basal melt - were initially difficult to untangle from the satellite data. After further analysis, the scientists found that although a strong El Niño changes wind patterns in West Antarctica in a way that promotes flow of warm ocean waters towards the ice shelves to increase melting from below, it also increases snowfall particularly along the Amundsen Sea sector.

The new data set from the study will allow researchers to check if their ocean models can correctly represent changes in the flow of warm water under ice shelves. Understanding what's causing the changes in the ice shelves is crucial for improving sea-level rise projections.

Melting of the ice shelves doesn't directly affect sea level rise, but they hold off the flow of grounded ice toward the ocean, which matters for sea-level rise. Laurie Padman, an oceanographer, states that the ice shelf response to ENSO climate variability can be used as a guide to how longer-term changes in global climate might affect ice shelves around Antarctica.

Paolo's PhD adviser, Fricker, emphasizes the importance of studying processes that are driving changes in the ice shelves to improve understanding of how grounded ice will change. The study provides insights into how Antarctic ice shelves respond to variability in global ocean and atmospheric conditions.

Unfortunately, the researcher currently working at NASA's Jet Propulsion Laboratory who led the study on the impact of El Niño on West Antarctic ice shelves is not named in the provided search results. Nonetheless, the findings of this study offer a significant step forward in understanding the complex interplay between climate events and Antarctic ice shelves.

Antarctic Ice Shelves Experiencing Significant Shifts Due to Intense El Nino Events, According to Latest Research