Science

Ocean currents moving heat are growing closer to collapse, study says

Published

7 months ago

February 11, 2024

An abrupt shutdown of Atlantic Ocean currents that could put large parts of Europe in a deep freeze is looking a bit more likely and closer than before as a new complex computer simulation finds a “cliff-like” tipping point looming in the future.

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A long-worried nightmare scenario, triggered by Greenland’s ice sheet melting from global warming, still is at least decades away if not longer, but maybe not the centuries that it once seemed, a new study in Friday’s Science Advances finds. The study, the first to use complex simulations and include multiple factors, uses a key measurement to track the strength of vital overall ocean circulation, which is slowing.

A collapse of the current – called the Atlantic Meridional Overturning Circulation or AMOC – would change weather worldwide because it means a shutdown of one of key the climate and ocean forces of the planet.

It would plunge northwestern European temperatures by 9°F to 27°F (5°C to 15°C) over the decades, extend Arctic ice much farther south, turn up the heat even more in the Southern Hemisphere, change global rainfall patterns and disrupt the Amazon, the study said. Other scientists said it would be a catastrophe that could cause worldwide food and water shortages.

“We are moving closer (to the collapse), but we we’re not sure how much closer,” said study lead author Rene van Westen, a climate scientist and oceanographer at Utrecht University in the Netherlands. “We are heading toward a tipping point.”

When this global weather calamity – grossly fictionalized in the movie “The Day After Tomorrow” – may happen is “the million-dollar question, which we unfortunately can’t answer at the moment,” van Westen said. He said it’s likely a century away but still could happen in his lifetime. He just turned 30.

“It also depends on the rate of climate change we are inducing as humanity,” van Westen said.

Studies have shown the AMOC to be slowing, but the issue is about a complete collapse or shutdown. The United Nations’ Intergovernmental Panel on Climate Change, which is a group of hundreds of scientists that gives regular authoritative updates on warming, said it has medium confidence that there will not be a collapse before 2100 and generally downplayed disaster scenarios. But van Westen, several outside scientists and a study last year say that may not be right.

Stefan Rahmstorf, head of Earth Systems Analysis at the Potsdam Institute for Climate Research in Germany, was not part of the research, but called it “a major advance in AMOC stability science.”

“The new study adds significantly to the rising concern about an AMOC collapse in the not too distant future,” Rahmstorf said in an email. “We will ignore this at our peril.”

University of Exeter climate scientist Tim Lenton, also not part of the research, said the new study makes him more concerned about a collapse.

An AMOC collapse would cause so many ripples throughout the world’s climate that are “so abrupt and severe that they would be near impossible to adapt to in some locations,” Lenton said.

There are signs showing that the AMOC has collapsed in the past, but when and how it will change in the future is still uncertain, said U.S. National Oceanic and Atmospheric Administration oceanographer Wei Cheng, who wasn’t part of the research.

The AMOC is part of an intricate global conveyor belt of ocean currents that move different levels of salt and warm water around the globe at different depths in patterns that helps regulate Earth’s temperature, absorbs carbon dioxide and fuels the water cycle, according to NASA.

When the AMOC shuts down, there’s less heat exchanged across the globe and “it really impacts Europe quite severely,” van Westen said.

For thousands of years, Earth’s oceans have relied on a circulation system that runs like a conveyor belt. It’s still going, but slowing.

The engine of this conveyor belt is off the coast of Greenland, where, as more ice melts from climate change, more freshwater flows into the North Atlantic and slows everything down, van Westen said. In the current system, cold, deeper, fresher water heads south past both Americas and then east past Africa.

Meanwhile saltier warmer ocean water, coming from the Pacific and Indian oceans, pushes past the southern tip of Africa, veers to and around Florida and continues up the U.S. East Coast on up to Greenland.

The Dutch team simulated 2,200 years of its flow, adding in what human-caused climate change does to it. They found after 1,750 years “an abrupt AMOC collapse,” but so far are unable to translate that simulated timeline to Earth’s real future. Key to monitoring what happens is a complicated measurement of flow around the tip of Africa. The more negative that measurement, the slower AMOC runs.

“This value is getting more negative under climate change,” van Westen said. When it reaches a certain point it’s not a gradual stop but something that is “cliff-like,” he said.

The world should pay attention to potential AMOC collapse, said Joel Hirschi, division leader at the United Kingdom’s National Oceanography Centre. But there’s a bigger global priority, he said.

“To me, the rapidly increasing temperatures we have been witnessing in recent years and associated temperature extremes are of more immediate concern than the AMOC shutting down,” Hirschi said. “The warming is not hypothetical but is already happening and impacting society now.”

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Science

The body of a Ugandan Olympic athlete who was set on fire by her partner is received by family

Published

23 hours ago

September 13, 2024

Anne Joseph

NAIROBI, Kenya (AP) — The body of Ugandan Olympic athlete Rebecca Cheptegei — who died after being set on fire by her partner in Kenya — was received Friday by family and anti-femicide crusaders, ahead of her burial a day later.

Cheptegei’s family met with dozens of activists Friday who had marched to the Moi Teaching and Referral Hospital’s morgue in the western city of Eldoret while chanting anti-femicide slogans.

She is the fourth female athlete to have been killed by her partner in Kenya in yet another case of gender-based violence in recent years.

Viola Cheptoo, the founder of Tirop Angels – an organization that was formed in honor of athlete Agnes Tirop, who was stabbed to death in 2021, said stakeholders need to ensure this is the last death of an athlete due to gender-based violence.

“We are here to say that enough is enough, we are tired of burying our sisters due to GBV,” she said.

It was a somber mood at the morgue as athletes and family members viewed Cheptegei’s body which sustained 80% of burns after she was doused with gasoline by her partner Dickson Ndiema. Ndiema sustained 30% burns on his body and later succumbed.

Ndiema and Cheptegei were said to have quarreled over a piece of land that the athlete bought in Kenya, according to a report filed by the local chief.

Cheptegei competed in the women’s marathon at the Paris Olympics less than a month before the attack. She finished in 44th place.

Cheptegei’s father, Joseph, said that the body will make a brief stop at their home in the Endebess area before proceeding to Bukwo in eastern Uganda for a night vigil and burial on Saturday.

“We are in the final part of giving my daughter the last respect,” a visibly distraught Joseph said.

He told reporters last week that Ndiema was stalking and threatening Cheptegei and the family had informed police.

Kenya’s high rates of violence against women have prompted marches by ordinary citizens in towns and cities this year.

Four in 10 women or an estimated 41% of dating or married Kenyan women have experienced physical or sexual violence perpetrated by their current or most recent partner, according to the Kenya Demographic and Health Survey 2022.

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The ancient jar smashed by a 4-year-old is back on display at an Israeli museum after repair

Published

2 days ago

September 11, 2024

Anne Joseph

TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.

Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.

Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.

The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.

The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.

It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.

Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.

Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.

Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.

Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.

Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.

The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”

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B.C. sets up a panel on bear deaths, will review conservation officer training

Published

4 days ago

September 10, 2024

Anne Joseph

VICTORIA – The British Columbia government is partnering with a bear welfare group to reduce the number of bears being euthanized in the province.

Nicholas Scapillati, executive director of Grizzly Bear Foundation, said Monday that it comes after months-long discussions with the province on how to protect bears, with the goal to give the animals a “better and second chance at life in the wild.”

Scapillati said what’s exciting about the project is that the government is open to working with outside experts and the public.

“So, they’ll be working through Indigenous knowledge and scientific understanding, bringing in the latest techniques and training expertise from leading experts,” he said in an interview.

B.C. government data show conservation officers destroyed 603 black bears and 23 grizzly bears in 2023, while 154 black bears were killed by officers in the first six months of this year.

Scapillati said the group will publish a report with recommendations by next spring, while an independent oversight committee will be set up to review all bear encounters with conservation officers to provide advice to the government.

Environment Minister George Heyman said in a statement that they are looking for new ways to ensure conservation officers “have the trust of the communities they serve,” and the panel will make recommendations to enhance officer training and improve policies.

Lesley Fox, with the wildlife protection group The Fur-Bearers, said they’ve been calling for such a committee for decades.

“This move demonstrates the government is listening,” said Fox. “I suspect, because of the impending election, their listening skills are potentially a little sharper than they normally are.”

Fox said the partnership came from “a place of long frustration” as provincial conservation officers kill more than 500 black bears every year on average, and the public is “no longer tolerating this kind of approach.”

“I think that the conservation officer service and the B.C. government are aware they need to change, and certainly the public has been asking for it,” said Fox.

Fox said there’s a lot of optimism about the new partnership, but, as with any government, there will likely be a lot of red tape to get through.

“I think speed is going to be important, whether or not the committee has the ability to make change and make change relatively quickly without having to study an issue to death, ” said Fox.

This report by The Canadian Press was first published Sept. 9, 2024.

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