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- Whether all of this means we're in a mass extinction or not is heavily debated. Dr Ceballos, the ecologist at Mexico City's UNAM university, says that he believes that we will have fully entered a mass extinction by the end of the year 2150, and that we could lose 70% of all plants and animals within the next two centuries.
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Sep 19, 2022 · According to the International Union for Conservation of Nature (IUCN) Red List of Threatened Species, around 41,000 — close to one-third of all assessed species — are currently threatened with...
- Joe Phelan
- Overview
- Related: Stunning Pictures of Dinosaur Fossils
- Ordovician-Silurian extinction - 444 million years ago
- Late Devonian extinction - 383-359 million years ago
- Permian-Triassic extinction - 252 million years ago
- Related: Life in the Permian Period
- Triassic-Jurassic extinction - 201 million years ago
- Related: Life in the Triassic Period
- Cretaceous-Paleogene extinction - 66 million years ago
- Extinction today
In the last 500 million years, life has had to recover from five catastrophic blows. Are humans dealing the planet a sixth?
More than 99 percent of all organisms that have ever lived on Earth are extinct. As new species evolve to fit ever changing ecological niches, older species fade away. But the rate of extinction is far from constant. At least a handful of times in the last 500 million years, 75 to more than 90 percent of all species on Earth have disappeared in a geological blink of an eye in catastrophes we call mass extinctions.
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This nearly whole, deep-black skull belongs to the most complete specimen of Tyrannosaurus rex on display in Europe, an individual nicknamed Tristan Otto. With 170 of its 300-odd bones preserved, this scientifically important but privately owned skeleton is currently at the Museum für Naturkunde in Berlin, Germany. Discovered in 2010 in Montana’s famed Hell Creek Formation of the late Cretaceous, the 40-foot-long fossil took four years to excavate and prepare.
This nearly whole, deep-black skull belongs to the most complete specimen of Tyrannosaurus rex on display in Europe, an individual nicknamed Tristan Otto. With 170 of its 300-odd bones preserved, this scientifically important but privately owned skeleton is currently at the Museum für Naturkunde in Berlin, Germany. Discovered in 2010 in Montana’s famed Hell Creek Formation of the late Cretaceous, the 40-foot-long fossil took four years to excavate and prepare.
Photography by Gerd Ludwig
Though the Cretaceous-Paleogene extinction is famous for being caused mainly by a huge asteroid, it’s the exception. The single biggest driver of mass extinctions appears to be major changes in Earth’s carbon cycle such as large igneous province eruptions, huge volcanoes that flooded hundreds of thousands of square miles with lava. These eruptions ejected massive amounts of heat-trapping gases such as carbon dioxide into the atmosphere, enabling runaway global warming and related effects such as ocean acidification and anoxia, a loss of dissolved oxygen in water.
The Ordovician period, from 485 to 444 million years ago, was a time of dramatic changes for life on Earth. Over a 30-million-year stretch, species diversity blossomed, but as the period ended, the first known mass extinction struck. At that time, massive glaciation locked up huge amounts of water in an ice cap that covered parts of a large south polar landmass. The icy onslaught may have been triggered by the rise of North America’s Appalachian Mountains. The large-scale weathering of these freshly uplifted rocks sucked carbon dioxide out of the atmosphere and drastically cooled the planet.
As a result, sea levels plummeted by hundreds of feet. Creatures living in shallow waters would have seen their habitats cool and shrink dramatically, dealing a major blow. Whatever life remained recovered haltingly in chemically hostile waters: Once sea levels started to rise again, marine oxygen levels fell, which in turn caused ocean waters to more readily hold onto dissolved toxic metals.
Starting 383 million years ago, this extinction event eliminated about 75 percent of all species on Earth over a span of roughly 20 million years.
In several pulses across the Devonian, ocean oxygen levels dropped precipitously, which dealt serious blows to conodonts and ancient shelled relatives of squid and octopuses called goniatites. The worst of these pulses, called the Kellwasser event, came about 372 million years ago. Rocks from the period in what’s now Germany show that as oxygen levels plummeted, many reef-building creatures died out, including a major group of sea sponges called the stromatoporoids.
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How One Brilliant Woman Mapped the Secrets of the Ocean Floor
Oceanic cartographer Marie Tharp helped prove the theory of continental drift with her detailed maps of the ocean floor. This animation by Rosanna Wan for the Royal Institution tells the fascinating story of Tharp’s groundbreaking work. The Short Film Showcase spotlights exceptional short videos created by filmmakers from around the web and selected by National Geographic editors. The filmmakers created the content presented, and the opinions expressed are their own, not those of National Geographic Partners.
It’s been hard to nail down the cause for the late Devonian extinction pulses, but volcanism is a possible trigger: Within a couple million years of the Kellwasser event, a large igneous province called the Viluy Traps erupted 240,000 cubic miles of lava in what is now Siberia. The eruption would have spewed greenhouse gases and sulfur dioxide, which can cause acid rain. Asteroids may also have contributed. Sweden’s 32-mile-wide Siljan crater, one of Earth’s biggest surviving impact craters, formed about 377 million years ago.
Some 252 million years ago, life on Earth faced the “Great Dying”: the Permian-Triassic extinction. The cataclysm was the single worst event life on Earth has ever experienced. Over about 60,000 years, 96 percent of all marine species and about three of every four species on land died out. The world’s forests were wiped out and didn’t come back in ...
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A sail-backed edaphosaurus forages amid a Permian landscape in this artist's depiction. These primitive predators, along with their close relatives the dimetrodons, though dinosaur-like in appearance, are actually considered the forerunners of mammals. Scientists think their large back fins were used to regulate body temperature.
Edaphosaurus
A sail-backed edaphosaurus forages amid a Permian landscape in this artist's depiction. These primitive predators, along with their close relatives the dimetrodons, though dinosaur-like in appearance, are actually considered the forerunners of mammals. Scientists think their large back fins were used to regulate body temperature.
Artwork by Interfoto Pressebildagentur/Alamy
Life took a long time to recover from the Great Dying, but once it did, it diversified rapidly. Different reef-building creatures began to take hold, and lush vegetation covered the land, setting the stage for a group of reptiles called the archosaurs: the forerunners of birds, crocodilians, pterosaurs, and the nonavian dinosaurs. But about 201 mil...
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An artist's rendering shows hatchling nothosaurs heading for the safety of water as a hungry but terrestrial Ticinosuchus attacks near a lagoon in ancient Switzerland. Nothosaurs lived during the mid- and late Triassic period and were among the earliest reptiles to take to the sea. Because nothosaurs may have had to come ashore to lay eggs, the eggs and hatchlings would have been vulnerable to Ticinosuchus. Yet once the hatchlings reached deeper waters, they were safe—for the moment.
Fleeing Nothosaurs
An artist's rendering shows hatchling nothosaurs heading for the safety of water as a hungry but terrestrial Ticinosuchus attacks near a lagoon in ancient Switzerland. Nothosaurs lived during the mid- and late Triassic period and were among the earliest reptiles to take to the sea. Because nothosaurs may have had to come ashore to lay eggs, the eggs and hatchlings would have been vulnerable to Ticinosuchus. Yet once the hatchlings reached deeper waters, they were safe—for the moment.
Artwork by DAMNFX
The Cretaceous-Paleogene extinction event is the most recent mass extinction and the only one definitively connected to a major asteroid impact. Some 76 percent of all species on the planet, including all nonavian dinosaurs, went extinct.
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Dinosaurs 101
Over a thousand dinosaur species once roamed the Earth. Learn which ones were the largest and the smallest, what dinosaurs ate and how they behaved, as well as surprising facts about their extinction.
One day about 66 million years ago, an asteroid roughly 7.5 miles across slammed into the waters off of what is now Mexico’s Yucatán Peninsula at 45,000 miles an hour. The massive impact—which left a crater more than 120 miles wide—flung huge volumes of dust, debris, and sulfur into the atmosphere, bringing on severe global cooling. Wildfires ignited any land within 900 miles of the impact, and a huge tsunami rippled outward from the impact. Overnight, the ecosystems that supported nonavian dinosaurs began to collapse. (Learn more about the last day of the dinosaurs’ reign.)
Global warming fueled by volcanic eruptions at the Deccan Flats in India may have aggravated the event. Some scientists even argue that some of the Deccan Flats eruptions could have been triggered by the impact.
Earth is currently experiencing a biodiversity crisis. Recent estimates suggest that extinction threatens up to a million species of plants and animals, in large part because of human activities such as deforestation, hunting, and overfishing. Other serious threats include the spread of invasive species and diseases from human trade, as well as pollution and human-caused climate change. (Explore National Geographic magazine's special issue on extinction.)
Today, extinctions are occurring hundreds of times faster than they would naturally. If all species currently designated as critically endangered, endangered, or vulnerable go extinct in the next century, and if that rate of extinction continues without slowing down, we could approach the level of a mass extinction in as soon as 240 to 540 years.
Climate change presents a long-term threat. Humans’ burning of fossil fuels has let us chemically imitate large igneous provinces, through the injection of billions of tons of carbon dioxide and other gases into Earth’s atmosphere each year. By total volume, these past volcanoes emitted far more than humans do today; the Siberian Traps released more than 1,400 times the CO2 than humans did in 2018 from burning fossil fuels for energy. However, humans are emitting greenhouse gases as fast as—or even faster than—the Siberian Traps, and Earth’s climate is rapidly changing as a result.
As mass extinctions show us, sudden climate change can be profoundly disruptive. And while we haven’t yet crossed the 75-percent threshold of a mass extinction, that doesn’t mean things are fine. Well before hitting that grim marker, the damage would throw the ecosystems we call home into chaos, jeopardizing species around the world—including us.
Feb 10, 2023 · Listen to the article. The world has entered the sixth extinction crisis with the loss of species having a devastating impact on the biodiversity crucial to human survival. The process of extinction can be stopped by building technology, solutions and processes that can help us secure animal DNA and begin to reverse the damage created by humans.
Even if the future brought nothing worse than the extinction of a significant proportion of all species now listed as Critically Endangered, that would amount to a very large increase in the total number of extinctions since 1500 CE.
Sep 15, 2020 · A bite from a rabies-infected animal is a very effective mode of disease transmission. And in the 20 years before Covid-19, SARs, MERs, swine flu, and avian flu all spilled over from animals.
Feb 14, 2020 · One-third of all animal and plant species on the planet could face extinction by 2070 due to climate change, a new study warns. Researchers studied recent extinctions from climate change to...
Oct 13, 2023 · Other studies have put the modern extinction rate closer to 1,000 times faster than pre-human extinction rates. And still others predict that this could rise to 10,000 times faster, if all species that are currently “threatened” go extinct within the next century.
