ANTARCTIC CIRCULATION - GEOGRAPHY
News: Will
climate change result in slowing down Antarctic circulation?
What's in the news?
● Antarctic circulation
could slow by more than 40% over the next three decades,
with significant implications for the oceans and climate.
● Such
decline of the ocean circulation will stagnate
the bottom of the oceans and generate further impacts, affecting climate and
marine ecosystems for centuries to come.
Key takeaways:
● Cold
water that sinks near Antarctica drives the deepest flow of the overturning
circulation - a network of currents that spans the world's oceans. The
overturning carries heat, carbon, oxygen and nutrients around the globe.
● This
influences climate, sea level and the productivity of marine ecosystems.
Overturning Circulations:
● The
“overturning circulation” of the oceans, driven
by the movement of denser water towards the sea floor, helps deliver heat,
carbon, oxygen and vital nutrients around the globe.
● Ocean
overturning allows nutrients to rise up from the bottom, with the Southern
Ocean supporting about three-quarters of global phytoplankton production, the
base of the food chain.
Study:
● According
to a release, Matthew England, Deputy Director of the ARC Centre for Excellence
in Antarctic Science (ACEAS) at the University of New South Wales, Sydney, says
the modeling shows that global carbon emissions continue at the current rate,
then the Antarctic overturning will slow by more than 40% in the next 30 years
and on a trajectory that looks headed towards collapse.
● As temperatures rise,
freshwater from Antarctica’s melting ice enters the ocean, reducing the
salinity and density of the surface water and diminishing that downward flow to
the sea’s bottom.
● The
study’s findings also suggest the ocean would not be able to absorb as much
carbon dioxide as its upper layers become more stratified, leaving more CO2 in
the atmosphere.