The increase in the strength of the El Niño-Southern Oscillation (ENSO) phenomenon that many of the current climate models indicate in the medium term will very likely lead to warming that "could accelerate the irreversible melting of the platforms and layers of ice in Antarctica", according to a study led by experts from the Commonwealth Scientific and Industrial Research Organization (CSIRO). the scientific agency of Australia, whose results have been published in the journal Nature Climate Change.
The authors note that climate models now show that El Niño variability leads to reduced warming near the surface, but accelerates warming of deeper ocean waters, increasing the impact in relatively remote areas such as the ice shelves of the Antarctica.
ENSO is a key driver of climate variability, as both its warm phase, El Niño, and its colder phase, La Niña, influence weather conditions around the world, including in Australia, the CSIRO experts recall.
Wenju Cai, lead author of this study and a world expert on the relationship between climate change and ENSO, explained that the research now being published is a critical step to better understand how Antarctica will be affected by climate change.
"Climate change is expected to increase the magnitude of ENSO, making both El Niño and La Niña stronger," Wenju Cai details in a note released by the CSIRO.
This new research shows that a stronger El Niño can accelerate the warming of deep waters on the Antarctic shelf, causing ice shelves and ice sheets to melt faster.
"Our modeling also revealed that warming around the edges of floating sea ice slows down during this process, which slows the melting of sea ice near the surface," says the study's lead author.
The associated winds around Antarctica are the mechanism driving this result. When ENSO variability increases, the intensity of the westerly winds along the shelf decreases. As a result, the upwelling of warm water around Antarctica cannot increase as much.
The research team examined 31 climate models that participated in Phase 6 of the Coupled Model Intercomparison Project (CMIP6) under historical forcings and a high emissions scenario.
Ariaan Purich, co-author of the study and a researcher at Monash University (Australia) insists that the effects of increased ENSO variability go beyond extreme weather risks and affect changes in Antarctic sea ice and ice shelves and layers. ice.
"This could have broad implications for the global climate system, so continuing to understand how ENSO will respond to climate change is a critical area of climate research," said Ariaan Purich.
