5 THINGS TO KNOW ABOUT THE ATLANTIC CURRENTS
The Atlantic Ocean’s current system, an engine of the Northern Hemisphere’s climate, could be weakening to such an extent that it could soon bring big changes to the world’s weather, a scientific study said on Thursday.
1 OCEAN RETAINING MORE HEAT
The Atlantic Meridional Overturning Circulation (AMOC) is a large system
of ocean currents that transports warm water from the tropics northward into the North Atlantic. As the
atmosphere warms due to increased greenhouse gas emissions, the surface ocean beneath retains
more heat.
2 CURRENT WEAKEST IN OVER 1,000 YEARS
Climate models have shown that the AMOC is at
its weakest in more than a 1,000 years. However, it has
not been known whether the weakening is due to a change in circulation or is it to do with the loss of
stability. The study, published in the journal Nature Climate Change, said
the difference is crucial.
3 IRREVERSIBLE TRANSITION?
“The loss of dynamical stability would imply that the AMOC has approached its critical threshold, beyond
which a substantial and in practice likely irreversible transition to the weak mode could occur,” said Niklas
Boers at the Potsdam Institute for Climate Impact Research and author
of the study.
4 SYSTEM COLLAPSE POSSIBLE
By analyzing the seasurface temperature and
salinity patterns of the Atlantic Ocean, the study said the weakening of the last century is likely to be associated with a loss of
stability. “The findings support the assessment that the AMOC decline is not
just a fluctuation or a linear response to increasing temperatures but likely means the approaching of a critical threshold beyond which the circulation system could
collapse,” Boers said.
5 LESS RAIN IN EUROPE, NORTH AMERICA
If the AMOC collapsed, it would increase cooling of the Northern Hemisphere, sea level rise in the Atlantic,
an overall fall in precipitation over Europe and North
America and a shift in monsoons in South America
and Africa, Britain’s Met Office said. Other climate models have said the AMOC will weaken over the coming century but that a collapse
before 2100 is unlikely.