<
https://www.theguardian.com/environment/2024/feb/09/atlantic-ocean-circulation-nearing-devastating-tipping-point-study-finds>
"The circulation of the Atlantic Ocean is heading towards a tipping point that
is “bad news for the climate system and humanity”, a study has found.
The scientists behind the research said they were shocked at the forecast speed
of collapse once the point is reached, although they said it was not yet
possible to predict how soon that would happen.
Using computer models and past data, the researchers developed an early warning
indicator for the breakdown of the Atlantic meridional overturning circulation
(Amoc), a vast system of ocean currents that is a key component in global
climate regulation.
They found Amoc is already on track towards an abrupt shift, which has not
happened for more than 10,000 years and would have dire implications for large
parts of the world.
Amoc, which encompasses part of the Gulf Stream and other powerful currents, is
a marine conveyer belt that carries heat, carbon and nutrients from the tropics
towards the Arctic Circle, where it cools and sinks into the deep ocean. This
churning helps to distribute energy around the Earth and modulates the impact
of human-caused global heating.
But the system is being eroded by the faster-than-expected melt-off of
Greenland’s glaciers and Arctic ice sheets, which pours freshwater into the sea
and obstructs the sinking of saltier, warmer water from the south.
Amoc has declined 15% since 1950 and is in its weakest state in more than a
millennium, according to previous research that prompted speculation about an
approaching collapse.
Until now there has been no consensus about how severe this will be. One study
last year, based on changes in sea surface temperatures, suggested the tipping
point could happen between 2025 and 2095. However, the UK Met Office said
large, rapid changes in Amoc were “very unlikely” in the 21st century.
The new paper, published in
Science Advances, has broken new ground by
looking for warning signs in the salinity levels at the southern extent of the
Atlantic Ocean between Cape Town and Buenos Aires. Simulating changes over a
period of 2,000 years on computer models of the global climate, it found a slow
decline can lead to a sudden collapse over less than 100 years, with calamitous
consequences."
Cheers,
*** Xanni ***
--
mailto:xanni@xanadu.net Andrew Pam
http://xanadu.com.au/ Chief Scientist, Xanadu
https://glasswings.com.au/ Partner, Glass Wings
https://sericyb.com.au/ Manager, Serious Cybernetics
