Transcript

10.16.25 · Science Show KY

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Speaker 1: Welcome to Radioized Diary of Science and Nature. Your reader's
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Kelly Taylor. I'll have articles on the topics of science
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and nature, but first a reminder that RADIOI is a
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reading service intended for people who are blind or have
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other disabilities that make it difficult to read printed material.
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Today we'll start with an article from Time magazine. The
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headline is the world's first climate tipping point has been crossed.
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This is dated October twelfth. The exact moment when Earth
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will reach its tipping points, moments at which human induced
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climate change will trigger irreversible planetary changes, has long been
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a source of debate for scientists, but they might be
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closer than we think. A report published today says that
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the Earth has passed its first climate tipping point. The
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second Global Tipping Points Report, published by the University of
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Exeter found that warm water coral reefs are passing their
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tipping point. Rising ocean temperatures, acidification, overfishing, and pollution are
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combining to cause coral bleaching and mortality, meaning that a
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large number of coral reefs will be lost unless the
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global temperature returns towards one degree warming or below. Quote.
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We're in a new climate reality, said Tim Linton, founding
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director at the Global Systems Institute at the University of Exeter,
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who led the report. Quote, We've crossed a tipping point
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in the climate system, and we're now sure we're going
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to carry on through one and a half degrees celsius
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of global warming above the prior industrial level, and that's
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going to put us in danger for crossing more climate
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tipping points. In quote, the planet is predicted to cross
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the one point five degree celsius threshold within the next
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five years, according to a report from the World Meteorological
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Association or organization. Once that threshold is reached, the planet
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will seem more frequent and intense extreme weather and strains
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on food production and water access impacts many nations vulnerable
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to climate change are already seeing. The authors define a
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tipping point as occurring when changes in a system become
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self perpetuating and difficult to reverse beyond a threshold, leading
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to substantial, widespread impacts. Scientists have found as many as
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twenty five major tipping points, including the Amazon rainforest transforming
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from a lush forest that stores carbon emissions to a
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dry savannah, and the permanent melting of polar ice whereby
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the dark open water absorbs more heat compared to white snow,
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encouraging further melting. One hundred and sixty scientists in twenty
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three countries compile the latest data and literature on the
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topic and found that in the years since launching the
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report in twenty twenty three, reefs around the world have
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begun passing their thermal tipping point. Quote. We've seen eighty
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percent of coral reefs experience unprecedented heat waves, bleaching events,
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and die back, said Linton. The widespread collapse of reef
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ecosystems would be devastating for marine and human life. Reefs
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help support fisheries and protect coastlines from storm searches and
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rising sea levels. Of all the tipping points, coral reefs
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have one of the lowest thresholds for rising temperatures, meaning
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it's no surprise that it's the first to be breached.
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There are other measures of the environment's health that scientists
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are also watching. A September report found that we've already
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passed seven of the nine planetary boundaries, including the ocean
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becoming more acidic and the transformation of natural landscapes. These
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are thresholds that keep Earth's systems hospitable to life and
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protect against breaching a tipping point. Today's report also found
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that the global temperature threshold required to triggle the trigger
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the widespread dieback of the American rainforest is lower than
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previously thought, with the lower end of the estimated range
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now at one point five degree c. The authors emphasize
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the need for urgent action to avoid this fate, including
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targeted investments in conservation and restoration to preserve the forest
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for the more than hundred million people who depend on it.
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They also warned that the National merid Meridional n HUM
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Atlantic Meridional overturning circulation OH, I know it is, Atlantic
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meridianal overturning circulation, a system of ocean currents that circulates
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water within the Atlantic Ocean, is at risk of collapse
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below an increase of two degrees sea of global warming
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above pre industrial temperatures. If this happens, it would trigger
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harsher winters in Northwest Europe, disrupt the West African and
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Indian monsoons, and decrease agricultural yields in much of the world.
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A number of positive changes are being made around the world,
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of course, as green alternatives like electric vehicles and solar
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panels become more widely adopted and affordable. Quote, there is
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growing evidence of what we call positive tipping points, where
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the change to zero emission technologies and behaviors is also
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becoming self propelling, Linton says. But if we want to
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avoid crossing further climate tipping points, there's more progress to
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be made. He adds, we know we need the solutions
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to accelerate if we're going to limit warming to a
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level that could limit the risks from the bad tipping
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points and the climate now. Next, we have an article
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from BBC Wildlife ecosystem Killers. Ten destructive, brutal animals that
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destroy entire habitats. This is from October thirteenth, Indiscriminate predators,
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insatiable grazers, ecosystem engineers, flagrant opportunists and invasive horrors. Here's
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our pick of the animals great and small that can
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change the world around them beyond recognition and not in
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a good way. Ten animals that destroy the entire ecosystems. First,
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the brown tree snake. The remote Pacific island of Guam
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was serpent free until around nineteen fifty, when the brown
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tree snake arrived from somewhere in its native range to
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the south. However, it got there, most likely as a
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stowaway on a boat or plane. It found a land
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teeming with birds, reptiles, and bats that had no defenses
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against its predatory instincts. By the time authorities started monitoring
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the situation in the nineteen eighties, there were more than
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one hundred snakes per hectare, and much of the damage
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had already been done. By nineteen ninety, just three species
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of native vertebrates, all small lizards, remained in significant numbers
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in the island's forests. The snake wiped out twelve of
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the twenty two native bird species, including the Guam flycatcher,
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which was found nowhere else in the world, and reduced
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numbers of another eight species by at least ninety percent.
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It drove six native lizards to extinction and is also
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implicated in the disappearance of the endemic Guam flying fox,
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which was last seen in nineteen sixty eight. Surprisingly, this
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ecological disaster has had dramatic consequences for the island's wider ecology.
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Bird pollinated plants are now setting fewer seeds, and loss
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of the vertebrates that disperse seeds is changing the species
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composition of the island's forests. Meanwhile, spider populations have increased
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fortyfold during the wet season since their avian predators disappeared
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the cane toad. Sometimes a cure can be more dangerous
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than the disease it's meant to be treating. That is
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surely the case with the cane toad, a native of
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South and Central America that was transported to Australia in
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the nineteen thirties to control beetles plaguing the sugar cane crops. Unfortunately,
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these gluttonous amphibians hunt on the ground, so they made
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little impact on the beetles, which feed high up in
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the plants. Instead, the toads turned their attentions to the
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native wildlife, swallowing pretty much anything that would fit in
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their mouths insects, frogs, reptiles, and small birds and mammals.
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But cane toads are not only dangerous in discriminate predators,
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they also are lethal prey quoals. Those are predatory marsupials, goanas,
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a type of large monitor lizard, snakes, and even freshwater
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crocodiles can be killed by the potent toxins secreted by
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glands on the frog's skin. In many invaded areas, quoals
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have vanished and goanas have crashed by more than ninety percent.
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The cane toad is a species that can wreak havoc
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at both ends of the food chain. Beaver, this big
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bucktooth rodent, is hailed for its ability to create to
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create habitats rather than destroy them by felling trees and
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damming streams. It engineers wetland ecosystems that boost aquatic biodiversity
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and as natural food defenses. But you can't make an
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omelet without breaking eggs. Valleys that once held bubbling streams,
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shady woodland, and wildflower meadows became quite literally swamped by
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standing water. Trees die dams block the passage of migratory fish,
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and species that require flowing water quietly disappear in the
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beaver's native ranges. These trade offs are part of long
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established ecological processes in places where beavers don't belong, though
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the downsides can be more striking. Beavers introduced from North
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to South America have destroyed swaths of native beech forest
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in Tierra del Fuego. Whether you see the activities of
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these quintessential ecosystem engineers as creative or destructive depends on
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where you stand when the water starts to rise. Rosy
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wolf snail the vast majority of terrestrial snails or vegetarians,
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and for good reason. Predators need to be fast, and
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yet speed is not something snails are known for. The
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rosy wolf snail, though, is very much a hunter. While
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it's not exactly nippy, it is crucially faster than its prey,
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other snails, which it hunts down by following their slime trails.
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Native to the southeastern United States, the rosy wolf snail
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was introduced to a number of Pacific islands, including Tahiti
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and Hawaii in the mid twentieth century in the hope
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that it would control the giant African land snail, which
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had become an invasive agricultural pest after its own introduction. Tragically,
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the rosy wolf snail turned out to prefer easier pickings
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the small, delicate native snails that had been evolving in
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splendid isolation on the various islands for hundreds of thousands
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of years. A massacre ensued. More than one hundred native
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snail species were driven to extinction within decades. Rats opportunistic
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and adaptable. Rats seem to flourish wherever life takes them.
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They are agile climbers, strong swimmers, fiercely intelligent, prolific breeders,
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catholic in their tastes, and have a knack for availing
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themselves of human modes of transportation between them. The black rat,
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brown rat, and pacific rat, all originally native to South
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and Eastern Asia, now infest more than eighty percent of
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the world's islands, and the transformation of habitats begins as
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soon as they have hopped ashore. Globally, rats are implicated
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in the extinction of more than seventy vertebrate species in
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the Chagos Archipelago. In the Indian Ocean, the densities of
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seabirds on on rat free islands are seven hundred sixty
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times higher than on infested ones. This has had dramatic
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effects on the wider ecosystem, which has historically been nourished
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by the guano depositing by the resident bird colonies. Even
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the coastal waters are affected to the extent that the
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coral reefs fringing rat free islands support around fifty percent
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more fish. The nile perch. Few introductions have caused such
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havoc as the nile perch's release into Lake Victoria in
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East Africa in the nineteen fifties. This giant predator, growing
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more than two meters long, was meant to boost fisheries.
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Arguably it succeeded, but at a huge ecological cost. In
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the fifteen thousand years since, climate changes created the world's
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second largest lake, evolution has worked its magic on a
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population of ciclid fish that arrived there soon after its formation.
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These founding mothers and fathers multiplied, dispersed, and diversified to
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fill a multitude of specialized niches. While some took to
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hunting in the open water or scraping algae from rocks,
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others strained particles from the sediment, crushed mollusks, or scavenged
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at the surface. A few even specialized in nibbling the
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fins and scales of their neighbors. Add to that the
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gaudy colors and elaborate courtship rituals that set species apart,
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and the result was a living evolutionary laboratory unrivaled anywhere
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in fresh water. To the nile perch, though it was
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all just food. Within a few decades, as many as
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two hundred of the lake's cyclid species were extinct. Many
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others now cling on in tiny populations, while some survive
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only in aquaria. The European rabbit. Don't be fooled by
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the endearing, twitchy nose and photogenic dandelion nibbling. The European
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rabbit has proved capable of causing ecological devastation around the world.
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Native to the Iberian Peninsula, it has been introduced to
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all continents except Antarctica for its fur and as a
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game animal. Most infamously, perhaps a handful released in Australia
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in the eighteen fifties soon became hundreds of millions, which
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gnawed through crops and native vegetation, stripping landscapes bare and
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turning fertile soils to dust. The problem was so overwhelming
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that authorities built the rabbit Proof Fence, the longest continuous
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barrier in the world at the time, over three thousand
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kilometers long, in a vain attempt to hold back the tide.
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New Zealand fared little better, and the destruction was compounded
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by efforts to control them with introduced stoats and weasels.
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These had a modest effect on the rabbits, but tragic
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consequences for native birds, including the laughing owl, which was
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driven into extinction by the early twentieth century. The domestic
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cat people have long enjoyed having cats around the place,
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not only for their company but also for their rodent
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control skills. Unfortunately, they don't stop it eating just vermin.
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In the US alone, pet and feral cats kill an
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estimated one point three to four billion birds every year,
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and cats introduced to islands around the world are implicated
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in fourteen percent of all the bird, mammal, and reptile
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extinctions in modern times. Take what happened on Stephens Island
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in the Cook Strait between New Zealand's North and South Islands.
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Until the eighteen nineties, it was an uninhabited, pristine refuge
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for many species that had already been ravaged by the
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Polynesian rat, which had arrived with the Mayoris. But when
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a new lighthouse was switched on in eighteen ninety four,
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the island became home to three lighthouse keepers, their families,
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nature for the children, and a succession of pet cats
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that quickly spawned a feral population that feasted on the
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island's bird life and reptiles, such as the tuatara, the
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sole living representative of an ancient lineage of lizard like
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animals that had already been eliminated from the mainland. The
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Stephens Island wren, a tiny, flightless songbird found nowhere else
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on Earth, was first described from a specimen killed by
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one of the cats, and seems to have disappeared completely
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by eighteen ninety nine. The feral cats were finally eradicated
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from the island by twenty twenty five, in a pioneering
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effort that provided an early lesson in how habitats can
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be restored to their former glory. Sea bird and reptile
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populations have rebounded, and the tuatara recovered to the point
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that individuals could be shipped to other islands. The wren, though,
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is gone forever the feral goat. A century after the
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removal of cats from Stephen's Island, habitat restoration efforts have
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been become increasingly ambitious. A case in point is Project Isabella,
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which aims to eradicate hundreds of thousands of feral goats
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from the Galapagos Archipelago. When goats arrived in the islands
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during the sixteen hundreds, deposited there by passing sailors as
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a living food store. The only native terrestrial mammals were
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a few species of bat. The islands would later become
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famous for the endemic birds and reptiles that were so
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influential on the development of Darwin's ideas on the mechanism
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of evolution. But as the goats multiplied, they posed an
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increasing threat to the native habitats on which the iconic
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finches and giant tortoises depend. Goats are hardy and adaptable,
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and their digestive systems can deal with plant toxins that
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would kill other herbivores, allowing them to eat anything and
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everything a botanical nature. On some islands, vast tracks have
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been stripped of vegetation and turned to dust, while forest
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trees have been unable to reproduce because the goats eat
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each and every seedling. Project Isabella is not yet complete.
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More than one hundred forty thousand goats have been removed
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from four hundred thousand hectares of land at a cost
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of at least ten and a half million dollars, but
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they continue to roam on three islands. The red grouse.
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It is neither an invader nor especially destructive in its
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own right, but the red grouse has managed to reconfigure
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the landscape of pretty much an entire country, or, more accurately,
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perhaps the landscape has been reconfigured around it. Native to
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the uplands of Britain and Ireland, and indeed found nowhere
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else in the world, the bird has long been hunted
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as game, and grouse shooting has become increasingly commercialized over
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the last couple of centuries to keep grouse numbers high.
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Vast tracts of the Scottish Highlands are managed as heather moorland.
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Since the mid nineteenth century, the heather itself has been
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burned in rotation, a practice known as mure burn, to
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provide the birds with young shoots to eat and other
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stands for cover, giving the hills a distinctive patchwork appearance.
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Trees are discouraged. Saplings that survive the flames are grazed
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by sheep and deer. Historically, predators such as raptors, foxes
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and stoats have been trapped or shot, and some illegal
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persecution continues today. They might be bonnie, but Scotland's heather
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clad hillsides are low and biodiversity, poor at storing carbon,
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and prone to erosion and flooding. They look wild, but
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they are managed intensively to serve the interests of a
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single species until the twelfth of August at least, which
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is when the shoe starts. Now from the Guardian we
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have this article which is headlined a new island erupted
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from the sea. Can it show us how nature works
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without human interference? This is dated October thirteenth. The crew
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of the Ilafer Ilafer iiO had just finished casting their
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nets off the coast of southern Iceland when they realized
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something was wrong. In the early morning gloom in November
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nineteen sixty three, a dark mass filled the sky over
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the Atlantic Ocean. They rushed to the radio, thinking that
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another fishing vessel was burning at sea, but no boats
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in the area were in distress. Then their trawler began
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to drift unexpectedly, unnerving the crew further. The cook scrambled
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to wake the captain, thinking they were being pulled into
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a whirlpool. Finally, through binoculars they spotted calm of ash
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bursting from the water and realized what was going on.
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A volcano was erupting in the ocean below. By the
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time the sun had risen, dark ash filled the sky
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and a ridge was forming just below the surface of
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the water. By the next morning it was ten meters high.
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A day later it was forty meters an island was
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being born. Two months later the rock was more than
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a kilometer long and one hundred and seventy four meters
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high at its peak. It was named Sertsee after the
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fire giant Seerter from norths Mythology Islanders and fissures from
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the nearby vest Manner Archipelago watched as lightning struck the
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volcanic eruption, which waxed and waned, and its intensity lighting
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up the winter half light. It would be two years
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before it stopped erupting completely. Quote. It is very rare
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to have an eruption where an island forms and is
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long lasting. It happens once every three thousand to five
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thousand years in this area, says Olga colbryn Villemordort, a
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geographer with the Natural Science Institute of Iceland. Those that
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do form are often quickly washed away by the ocean.
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She says, the emergence of Certsee presented researchers with a
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precious scientific opportunity. They could observe how life colonizes and
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spreads on an island away from human interference that has
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overtaken much of the Earth. Other islands have emerged since
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the nineteen sixties, but scientists say they have not been
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as ecologically stable. The last time something similar took place
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before Certsei's emergence was the birth of Annak Krakatoa, Indonesia
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in nineteen twenty seven, but it was quickly contaminated by humans.
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Icelandic researchers were adamant that this time would be different.
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In nineteen sixty five, was placed under formal protection by
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the government. Only researchers and the odd journalists under strict
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supervision would be allowed to visit. No sheep would ever
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be allowed to graze there. The same year, the first
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plant was spotted, a clump of sea rocket brought over
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the waves from the Icelandic mainland. The first scientists that
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stepped on Certseey in nineteen sixty four could see that
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seeds and plant residues had been washed ashore. Birds were
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even coming to the island to see what was going on.
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The eruption was still going on. When they spotted the
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first plant, it was very quick, says Oga. Scientists had
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expected algae and mosses to be the first colonizers, building
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up a base of soil that would eventually support vascular plants,
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but that step was skipped completely. More plants were washed
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ashore in following years, and some clung to the island's
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bare volcanic rock, but after a decade the changes seemed
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to stall. Pauvel Voskowitz, director of botany at the Natural
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Science Institute, says people thought what now. Around ten species
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had colonized Certsei. At that point the plant cover was
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really scarce. But then the birds arrived. In the early
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nineteen eighties, black backed gulls started to nest on sections
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of the island, sheltering in one of the stormiest parts
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of the Atlantic Ocean. Their arrival kicked off in explosion
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of life. Guano carried seeds that quickly spread grasses along
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the island, fed in turn by the nutrients from the birds.
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For the first time, the whole areas of bare rock
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became green. Voskovitch says, it's surprising. From the times of Darwin,
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biologists thought it was just plant species with fleshy fruits
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that could travel with birds, but the species on Certsi
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do not have fleshy fruits. Almost all of the seeds
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on Sertsi were brought in the feces of the gullste our.
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A lesson from this living laboratory is that recovery after
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disturbance does not always follow a single predictable path. He says, instead,
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it is shaped by multiple, sometimes surprising forces. Today, gray
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seals are the latest arrivals to change to cause changes
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in the island's biodiversity. The volcanic rock has become a
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crucial haulout site where seals come ashore to rest and molt,
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as well as a breeding ground where they can raise
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their young safe from the orcas lurking nearby. Their feces
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urine en placentas from birth are bringing nitrogen to the island,
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helping life spread further, but researchers warn that the colonization
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of Certsi will one day go into reverse. The gray
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seal haul out site is one of the areas slowly
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being eroded by the ocean. By the end of the century,
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scientists project that little will be left from that second
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of the island. Its biodiversity will probably pique then fall
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over time, eventually leaving a rock with sharp cliffs alone
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in the Atlantic. But the researchers say that lessons will
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remain search He demonstrates that even in the harshest environments,
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resilience and renewal are possible. It offers hope and practical
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lessons for rehabilitating ecosystems damaged by war, pollution, or exploitation.
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If space is given, nature will always find ways to return,
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often faster and more creatively than we expect. Well, that's
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it for today's Diary of Science and Nature. Your reader
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was Kelly Taylor. Now stay tuned for further programming on
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