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Gulf System collapse: Atlantic Meridional Overturning Circulation shutdown predicted


Experts have predicted that a devastating climate event with disastrous consequences could unfold as early as 2025 without urgent, meaningful action.

The Gulf System is in danger of collapsing according to a new study in the journal Nature Communications.

If it does the subsequent shutting down of vital ocean currents – Atlantic Meridional Overturning Circulation (Amoc) – would have catastrophic climate effects.

Rain responsible for growing food for billions of people across India, South America and west Africa would be disrupted, while storms would increase and temperatures would drop in Europe.

The sea level would rise significantly up the eastern coast of North America, and the Amazon rainforest and Antarctic ice sheets would further be endangered.

Prof Peter Ditlevsen from the University of Copenhagen in Denmark, who led the study, said: “I think we should be very worried,” The Guardian reported.

“This would be a very, very large change. The Amoc has not been shut off for 12,000 years.”

If global carbon emissions are not dramatically reduced, the collapse could happen between 2025 and 2095, according to researchers.

Previous changes in temperature of up to 10 degrees occurred over a few decades, however those changes happened during ice ages.

From 115,000 to 12,000 years ago, the Amoc collapsed and restarted repeatedly in the cycle of ice ages.

An ice age isn’t on the cards for the next few years, making the climate tipping point one that scientists have particular concern about, especially given the continued rise of global temperatures.

Warm ocean water is carried northwards towards the pole by Amoc where it cools then sinks, driving the Atlantic’s currents.

Because Greenland’s ice caps have been melting and generating an influx of freshwater, the currents have been getting increasingly smothered.

Research last year showed five worrisome tipping points may have already been surpassed because of the 1.1 degree global heating, including the beginning of the Amoc shutdown, an abrupt melting of carbon-rich permafrost, and the melting of Greenland’s ice caps.

The projections outlined in the study, other scientists have argued, have limitations in that uncertainties in underlying data leave quite a bit of room for interpretation.

Still, they all agreed the possibility of an Amoc collapse was cause for extreme concern and should prompt rapid action on carbon emissions.

The study profiled sea surface temperature from as far back as 1870 to examine how Amoc currents changed over time.

Dr Ditlevsen said records worked “surprisingly well” in mapping out when the tipping point was likely to occur.

Further statistical examining however added a layer of uncertainty in the projection.

Scientists have previously said the potential collapse of Amoc must be avoided “at all costs”.

Ocean temperature hits potential record

This all comes amid a raging heatwave in the northern hemisphere.

Shallow waters off south Florida topped 37.8C for several hours on Monday, potentially setting a new world record with temperatures more commonly associated with hot tubs.

The readings were taken from a single buoy in Manatee Bay, about 60km southwest of Miami, at a depth 1.5m.

A peak temperature of 37.8C was recorded at 6pm local time, but it remained just below that for about four hours, official data showed.

Jeff Masters, a meteorologist and former government scientist, tweeted that while there was no official world record for sea surface temperature, a 2020 scientific paper found that the previous high might have been 37.61C recorded in Kuwait Bay.

However, since the new measurement was taken near land, “contamination of the measurement by land effects and organic matter in the water might…invalidate the record,” Masters said.

“Unless there is photographic proof that debris was not present, it would be difficult to (verify) the record as valid,” he added on social media.

The sauna-like conditions might be enjoyable for some humans, but sustained extreme heat is devastating for coral reef ecosystems and the species that depend on them.

It comes days after the nonprofit Coral Reef Foundation (CRF) said that a reef in south Florida which it had been working to restore had been devastated.

“CRF teams visited Sombrero Reef, a restoration site we’ve been working at for over a decade. What we found was unimaginable — 100 per cent coral mortality,” said the organization’s Phanor Montoya-Maya, in a statement.

About 25 percent of all marine species are found in, on, or around coral reefs, rivaling the biodiversity of tropical rainforests, according to the US National Oceanic and Atmospheric Administration.

Across the globe, the Mediterranean Sea reached its highest temperature on record on Monday during an exceptional heatwave, Spanish researchers told AFP on Tuesday.

“We attained a new record… in the daily median sea surface temperature of the Mediterranean: 28.71,” Spain’s Institute of Marine Sciences said.

The previous record was on August 23, 2003, with a median value of 28C. July 2023 is on track to be the hottest absolute month on record, as well as the hottest in potentially thousands of years, according to NASA climatologist Gavin Schmidt.

“We are seeing unprecedented changes all over the world,” he said last week, with records being broken on land and in the sea, and the effects mostly attributable to human-caused climate change.

— with AFP


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