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World’s Largest Iceberg Breaks Free, Heads toward Southern Ocean

A satellite imagery of the world's largest iceberg, named A23a, seen in Antarctica, November 15, 2023. (Courtesy of European Union/Copernicus Sentinel-3/Handout via Reuters)
A satellite imagery of the world's largest iceberg, named A23a, seen in Antarctica, November 15, 2023. (Courtesy of European Union/Copernicus Sentinel-3/Handout via Reuters)
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World’s Largest Iceberg Breaks Free, Heads toward Southern Ocean

A satellite imagery of the world's largest iceberg, named A23a, seen in Antarctica, November 15, 2023. (Courtesy of European Union/Copernicus Sentinel-3/Handout via Reuters)
A satellite imagery of the world's largest iceberg, named A23a, seen in Antarctica, November 15, 2023. (Courtesy of European Union/Copernicus Sentinel-3/Handout via Reuters)

The world's largest iceberg is on the move for the first time in more than three decades, scientists said on Friday.

At almost 4,000 square km (1,500 square miles), the Antarctic iceberg called A23a is roughly three times the size of New York City.

Since calving off West Antarctica's Filchner-Ronne Ice Shelf in 1986, the iceberg — which once hosted a Soviet research station — has largely been stranded after its base became stuck on the floor of the Weddell Sea.

Not anymore. Recent satellite images reveal that the berg, weighing nearly a trillion metric tons, is now drifting quickly past the northern tip of the Antarctic Peninsula, aided by strong winds and currents.

It's rare to see an iceberg of this size on the move, said British Antarctic Survey glaciologist Oliver Marsh, so scientists will be watching its trajectory closely.

As it gains steam, the colossal berg will likely be launched into the Antarctic Circumpolar Current. This will funnel it toward the Southern Ocean on a path known as "iceberg alley" where others of its kind can be found bobbing in dark waters.

Why the berg is making a run for it now remains to be seen.

"Over time it's probably just thinned slightly and got that little bit of extra buoyancy that's allowed it to lift off the ocean floor and get pushed by ocean currents," said Marsh. A23a is also among the world's oldest icebergs.

It's possible A23a could again become grounded at South Georgia island. That would pose a problem for Antarctica's wildlife. Millions of seals, penguins, and seabirds breed on the island and forage in the surrounding waters. Behemoth A23a could cut off such access.

In 2020, another giant iceberg, A68, stirred fears that it would collide with South Georgia, crushing marine life on the sea floor and cutting off food access. Such a catastrophe was ultimately averted when the iceberg broke up into smaller chunks — a possible end game for A23a as well.

But "an iceberg of this scale has the potential to survive for quite a long time in the Southern Ocean, even though it's much warmer, and it could make its way farther north up toward South Africa where it can disrupt shipping," said Marsh.

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Varieties

Scientists Seek Miracle Pill to Stop Methane Cow Burps

A cow that's part of study on reducing methane emitted by cow burps stands in an exclosure at UC Davis in Davis, California on October 23, 2024. (AFP)
A cow that's part of study on reducing methane emitted by cow burps stands in an exclosure at UC Davis in Davis, California on October 23, 2024. (AFP)
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Scientists Seek Miracle Pill to Stop Methane Cow Burps

A cow that's part of study on reducing methane emitted by cow burps stands in an exclosure at UC Davis in Davis, California on October 23, 2024. (AFP)
A cow that's part of study on reducing methane emitted by cow burps stands in an exclosure at UC Davis in Davis, California on October 23, 2024. (AFP)

A scientist guides a long tube into the mouth and down to the stomach of Thing 1, a two-month-old calf that is part of a research project aiming to prevent cows from burping methane, a potent greenhouse gas.

Paulo de Meo Filho, a postdoctoral researcher at University of California, Davis, is part of an ambitious experiment aiming to develop a pill to transform cow gut bacteria so it emits less or no methane.

While the fossil fuel industry and some natural sources emit methane, cattle farming has become a major climate concern due to the sheer volume of the cows' emissions.

"Almost half of the increase in (global) temperature that we've had so far, it's been because of methane," said Ermias Kebreab, an animal science professor at UC Davis.

Methane, the second largest contributor to climate change after carbon dioxide, breaks down faster than CO2 but is more potent.

"Methane lives in the atmosphere for about 12 years" unlike carbon dioxide which persists for centuries, Kebreab said.

"If you start reducing methane now, we can actually see the effect on the temperature very quickly."

Filho uses the tube to extract liquid from Thing 1's rumen -- the first stomach compartment containing partially digested food.

Using the rumen liquid samples, the scientists are studying the microbes that convert hydrogen into methane, which is not digested by the cow but instead burped out.

A single cow will burp roughly 220 pounds (100 kilograms) of the gas annually.

- 'Social critters' -

Thing 1 and other calves receive a seaweed-supplemented diet to reduce methane production.

Scientists hope to achieve similar results by introducing genetically modified microbes that soak up hydrogen, starving methane-producing bacteria at the source.

However, the team proceeds cautiously.

"We can't just simply cut down methane production by removing" methane-making bacteria, as hydrogen could accumulate to the point of harming the animal, warned Matthias Hess, who runs the UC Davis lab.

"Microbes are kind of social critters. They really like to live together," he said.

"The way they interact and affect each other impacts the overall function of the ecosystem."

Hess's students test different formulas in bioreactors, vessels that reproduce microorganisms' living conditions in a stomach from movements to temperature.

- More productive cows -

The project is being carried out at UC Davis as well as UC Berkeley's Innovative Genomics Institute (IGI).

IGI scientists are trying to identify the right microbe -- the one they hope to genetically alter to supplant methane-producing microbes.

The modified microorganisms will then be tested at UC Davis in the lab and in the animals.

"Not only are we trying to reduce methane emissions, but you also increase the feed efficiency," said Kebreab.

"Hydrogen and methane, they are both energy, and so if you reduce that energy and redirect it to something else... we have a better productivity and lower emissions at the same time."

The ultimate goal is a single-dose treatment administered early in life, since most cattle graze freely and can't receive daily supplements.

The three research teams have been given $70 million and seven years to achieve a breakthrough.

Kebreab has long studied sustainable livestock practices and pushes back against calls to reduce meat consumption to save the planet.

While acknowledging this might work for healthy adults in developed nations, he pointed to countries like Indonesia, where the government is seeking to increase meat and dairy production because 20 percent of children under five suffer from stunted growth.

"We can't tell them to not eat meat," he said.