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Tag: polynesia

  • The Surprising Ingredient That Helped Polynesians Conquer the Pacific

    The Surprising Ingredient That Helped Polynesians Conquer the Pacific

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    Sweet potatoes are a very versatile tuber. You can roast them. You can bake them into a pie. You can turn them into the third best type of french fry. And apparently, you can make them an integral part of colonizing Polynesian islands.

    Sweet potatoes are not indigenous to Polynesia, having arisen thousands of miles away in Central and South America. Even so, the tasty root vegetable has become a staple of the islands’ cuisine. While it was known that the crop had arrived in eastern Polynesia some time after human settlement in 900 CE, and then spread westward towards New Zealand, scientists have debated exactly how and when it got there. Some evidence suggests sweet potato seeds reached the region through natural means, such as birds, wind, and sea currents. Now, new research hints that the crop’s presence was a major factor in enabling human expansion across the Polynesian islands.

    A team of archaeologists, led by University of Otago professor Ian Barber, scoured the New Zealand island Te Wāhipounamu for remains of ancient kūmara, as the Maori call sweet potatoes. They found what they were looking for at Triangle Flat, an area that was once home to a Maori farming complex. In the sand, they located sweet potato granules, which they then carbon dated.

    Results showed that the crop could have been planted as early as 1290 CE, over 100 years earlier than previously believed on the island, and around the same time that settlers first began colonizing the southernmost Polynesian islands. As Barber wrote in his ensuing study, published Wednesday in the journal Antiquity, the findings suggest sweet potatoes were among the first crops planted by colonizers. In fact, the availability of sweet potatoes as a crop may have been among the factors that made settling the islands possible in the first place.

    The vegetable is known for its hardiness, as well as for the speed at which it grows. Polynesia is a vast network of over 1,000 islands, and settlers needed hardy crops to sustain themselves as they spread to new territories with cooler climates than those of islands nearer the equator. In a press release, Barber suggested that Polynesians may have been galvanized by the knowledge they had such a robust food source at their disposal.

    “American sweet potato resilience, as bequeathed by continental evolution, may have helped motivate early migrants to cross cooler waters for southern Polynesian islands where kūmara would outperform,” he said.

    There could be some greater impacts of Barber’s research. According to the International Potato Center, more than 105 million metric tons of the crop are produced globally each year, making it the world’s fifth largest crop. Climate change, however, threatens to affect production, as regions that produce a large amount of the supply could warm dramatically by 2070. Barber expressed hope that studying the spread of sweet potatoes could uncover new ways to improve the crop’s resilience. If that happens, you’ll know who to thank for saving your favorite Thanksgiving side dish.

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    Adam Kovac

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  • Lightning in the ‘cataclysmic’ Tonga volcano eruption shattered ‘all records’ | CNN

    Lightning in the ‘cataclysmic’ Tonga volcano eruption shattered ‘all records’ | CNN

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    CNN
     — 

    When the Hunga Tonga-Hunga Ha’apai volcano erupted in January 2022, it sent shockwaves around the world. Not only did it trigger widespread tsunami waves, but it also belched an enormous amount of climate-warming water vapor into the Earth’s stratosphere.

    Now researchers in a new report have unveiled something else: the eruption set off more than 25,500 lightning events in just five minutes. Over the course of just six hours, the volcano triggered nearly 400,000 lightning events. Half of all the lightning in the world was concentrated around this volcano at the eruption’s peak.

    The “cataclysmic eruption” shattered “all records,” according to the report from Vaisala, an environmental monitoring company that tracks lightning around the world.

    “It’s the most extreme concentration of lightning that we’ve ever detected,” Chris Vagasky, meteorologist and lightning expert at Vaisala, told CNN. “We’ve been detecting lightning for 40 years now, and this is really an extreme event.”

    The annual report by Vaisala found that 2022 was a year of extremes for lightning. Lightning increased in the US in 2022, with more than 198 million lightning strokes — 4 million more than what was observed in 2021, and 28 million more than 2020.

    “We are continuing an upward trend in lightning,” Vagasky said.

    The World-Wide Lightning Location Network, another lightning monitoring network led by the University of Washington, which is not involved with the report, said Vaisala’s findings about global lightning as well as the Hunga volcano are consistent with their own observations.

    “We can do this because the stronger eruptions generate lightning, and lightning sends detectable radio signals around the world,” Robert Holzworth, the director of the network, told CNN. “The Hunga eruption was absolutely impressive in its lightning activity.”

    Researchers have used lightning as a key indicator of the climate crisis, since the phenomenon typically signals warming temperatures. Lightning occurs in energetic storms associated with an unstable atmosphere, requiring relatively warm and moist air, which is why they primarily occur in tropical latitudes and elsewhere during the summer months.

    But in 2022, Vaisala’s National Lightning Detection Network found more than 1,100 lightning strokes in Buffalo, New York, during a devastating lake-effect snowstorm that dumped more than 30 inches of snow in the city, but piled historic totals in excess of 6 feet in the surrounding suburbs along Lake Erie. Lake-effect snow occurs when cold air blows over warm lake water, in this case from the Great Lakes. The large difference in temperature can cause extreme instability in the atmosphere and lead to thunderstorm-like lightning even in a snow storm.

    More than 1,100 lightning strokes were detected in Buffalo, New York, during a devastating lake-effect snowstorm that dumped more than 30 inches of snow in the city, but piled historic totals in excess of 6 feet in the surrounding suburbs along Lake Erie.

    The report noted that many of these lightning events happened near wind turbines south of Buffalo, which Vagasky said was significant. He explained that the ice crystal-filled clouds were lower to the ground than usual, scraping just above the blades of the turbines.

    “That can cause what is known as self-initiated upward lightning,” Vagasky said. “So the lightning occurs because you have charged at the tip of this wind turbine blade that is really close to the base of the cloud, and it’s really easy to get a connection of the electric charge.”

    This is an area of ongoing research, he said, as the country turns to more clean energy alternatives.

    “We’re seeing bigger and bigger wind turbines, and certainly as we’re putting in more and more wind energy and renewable energy, lightning is going to play a role in that,” he said.

    The report comes after an unusual year in 2021, when they found lightning strokes increased significantly in the typically frozen Arctic region, which scientists say is a clear sign of how the climate crisis is altering global weather.

    “Lightning in polar regions wasn’t mentioned [in this year’s Vaisala report], but our global lightning network shows a trend for much more lightning in the northern polar regions,” Michael McCarthy, research associate professor and associate director of the World Wide Lightning Location Network, told CNN. “That trend closely tracks the observed average temperature changes over the northern hemisphere.

    “This close tracking suggests, but does not prove, a climate change effect,” McCarthy added.

    Vagasky said lightning in colder areas will only amplify as the planet warms, noting that meteorologists and climatologists have been collecting more data to not only make the climate connections clear but also keep people safe.

    “That’s why they’ve named lightning as an essential climate variable,” he said, “because it’s important to know where it’s occurring, how much is occurring, and so you can see how thunderstorms are trending as a result of changing climates.”

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