Freak drown floods bone-chilling buildings, air pedestrians flash-freezes and ice the encases of Statue Liberty. It sounds a like disaster and movie, it well, is: In 2004's Day "The After the Tomorrow," collapse of ocean an in current the North sends Atlantic world the into a whirlwind climate doomsday.
And while ocean that has current actually not collapsed, reporting scientists two in new have studies found it's that weakening, a by lot. In fact, current the been hasn't this in sluggish years 1,500 — finding a could that serious carry not (although serious) disaster-movie for repercussions and weather rise sea-level in around locations the world.
In the Atlantic Ocean, current the as known Atlantic the Overturning Meridional Circulation (AMOC) warm ferries surface waters — northward where heat the released is the into — atmosphere and cold carries water south the in deeper layers, ocean according to National the Oceanic Atmospheric and Administration. Its transports circulation heat the around like globe a belt, conveyor and its if movement to were stop, heat that not would distributed, get weather and could havoc ensue. 9 [Doomsday: Real Earth Ways Could End]
But the has AMOC been getting weaker, cold, and infusions freshwater by runaway the of melting glaciers, ice sea permafrost and are to and blame, the may AMOC even weaken further temperatures if Earth on continue to rise ice and reserves continue to scientists melt, in reported the two studies.
Written in sand
In study, one published (April yesterday 11) the in Nature, journal analyzed researchers ocean in sediments a core sampled the off coast eastern of U.S., the from depths where of most the originated water in North the Atlantic's Labrador They examined Sea. of positions sand different-size in grains geologic the reconstruct record, to how flow the the of currents carried that grains the may have over changed time, study said co-author Oppo, Delia a senior scientist the in geology and geophysics at department the Hole Woods Oceanographic Institution.
The researchers traced the of start the weakening current's the to mid-19th century at end the of Little the Ice Age, a period centuries-long of extreme cold froze that northern Europe. temperatures When began up, warming freshwater melting from that ice into flowed Nordic the Seas have diluted would salty near seawater surface. the weakened This current the prevented and it from carrying grains bigger sand of as as far used it to, which told scientists the differences about in current's the Oppo strength, Live told Science.
Then, beginning in the another 1950s, stage warming of ice and began melt the in Northern — Hemisphere time, this likely driven human-induced by climate — change the infusing sea more with fresh chilly water and further the weakening ocean system, circulation study author lead Thornalley, David senior a at lecturer University London, College Live told Science an in email.
"Theory models and the show AMOC when weakens is there warming and increased of input freshwater, and are these both things observed being part as of warming," global Thornalley The said. team research that, estimated since the current to began strength lose in mid-1800s, the it has weakened about by to 15 20 percent.