Strengthening El Niño will accelerate the melting of ice in Antarctica

Scientists from the Australian National Science Agency CSIRO have shown that a stronger El Niño in the future could accelerate the irreversible melting of ice shelves and ice sheets in Antarctica. This is reported in an article published in the journal Nature Climate Change.

The research team studied 31 climate models that were used in CMIP6, a project to harmonize about 100 climate models in use. It turned out that the effects of El Niño variability go beyond the extreme weather risks predicted so far and significantly affect Antarctic sea ice, ice shelves and shields.

El Niño is a phase of the Southern Oscillation, which is a natural fluctuation in the surface water temperature of the equatorial Pacific Ocean. This phenomenon recurs at irregular intervals of 2-7 years and lasts an average of five years. El Niño contributes to abnormally high temperatures and droughts that affect developing countries dependent on agriculture and fisheries.

Strengthening El Niño could accelerate the warming of deep waters on the Antarctic shelf. During this process, the heating at the edges of the floating sea ice slows down, which also slows down the melting of the sea ice near the surface. This is due to a decrease in the rise of deeper and warmer waters, which, in turn, slows down the intensification of westerly winds along the shelf. As a result, La Niña, the opposite phase of the Southern Oscillation, also intensifies.