[ad_1]
There was a time when life on Earth almost disappeared. The "Great Death," the greatest extinction ever recorded on the planet, occurred 250 million years ago and was largely caused by greenhouse gases in the world. atmosphere. Now scientists are beginning to see alarming similarities between the Great Dying and what's happening in our atmosphere right now.
Scientists point to this similarity in a new exhibit presented at the Smithsonian National Museum of Natural History in Washington, DC.
The new Deep Time exhibition in the David H. Koch Fossil Room of the Smithsonian National Museum of Natural History in Washington, D.C.
Smithsonian
hide legend
activate the legend
Smithsonian
The new Deep Time exhibition in the David H. Koch Fossil Room of the Smithsonian National Museum of Natural History in Washington, D.C.
Smithsonian
The crown jewel of the Deep Time exhibition is the museum's first true museum. Tyrannosaurus rex. His skeleton rests on the bones of a triceratops lying, a clawed foot retaining the unfortunate herbivore and clenched jaws on his head, ready to bite like a slab.
"We like to say, come to the dinosaurs, stay for everything else," says Scott Wing, one of the conservatives.
The theme of the exhibition is the interdependence of life through geological time. The exhibition shows, for example, how plants at the bottom of the food chain supported everything from insects to apatosaurs of 20 tons. And how insects have helped shape the type of forests that have evolved and changed over millions of years.
Wing likes that – he's a botanist. "I am a chauvinist of photosynthesis," he says. "The whole ecosystem is based on photosynthesis." And because life, from toads to tyrannosaurs, is connected from the bottom up, all the tissue can disintegrate when something serious happens on Earth. And this is due to global warming.
Scott Wing, researcher in geology and curator of paleobotany, in his office at the Smithsonian Museum.
Ryan Kellman / NPR
hide legend
activate the legend
Ryan Kellman / NPR
Scott Wing, researcher in geology and curator of paleobotany, in his office at the Smithsonian Museum.
Ryan Kellman / NPR
This is explained in the section of the exhibition on the dying great. About 250 million years ago, a huge volcanic field erupted in present-day Siberia. He spewed lava that burned layers of limestone and coal and filled the atmosphere with carbon dioxide and pollution, probably for millions of years. This in turn warmed the planet, made the oceans acidic and removed oxygen. More than 90% of the species present in the oceans have disappeared, as well as two thirds of those found on the mainland.
There have been other massive extinctions, like the one that wiped out the dinosaurs about 65 million years ago, but this one, at the end of the Permian, was mainly caused by too much of carbon dioxide in the atmosphere. And the Smithsonian often notes in his exhibition that the current global warming is already seen once again.
"We can learn by studying the past," says Wing. "These are also the processes observed by Earth scientists today."
Part of the Deep Time exhibition is devoted to mass extinction called "the big murder". More than 90% of the species present in the oceans have disappeared, as well as two thirds of the terrestrial species.
Smithsonian
hide legend
activate the legend
Smithsonian
Part of the Deep Time exhibition is devoted to mass extinction called "the big murder". More than 90% of the species present in the oceans have disappeared, as well as two thirds of the terrestrial species.
Smithsonian
One of them is Curtis Deutsch from the University of Washington, whose research has helped inform the Smithsonian Conservatives. "The same things that caused the Great Dying now occur in our ocean as a result of human activities," he says, "not to the same degree, but in the same sense."
Currently, the planet has warmed to nearly 2 degrees Fahrenheit on average above what it was before the industrial revolution, although at the current rate it can heat up several degrees more . The Great Dying has experienced a warming increase of four or five times higher.
But it happened gradually. So, Deutsch thought, why not recreate in a computer the greenhouse of the dying great, a model that simulates global warming, and see how the present ocean species will behave? It could increase the carbon dioxide level, which would increase the temperature and reduce the oxygen in the oceans. Then he could observe that parts of the ocean were starting to become deadly.
The first thing that happens is that you start seeing a local loss of species as they move in response to global warming, "he says.
But some parts of the planet were more indulgent. "We discovered something surprising and new, I think," says Deutsch, "and that's the fact that extinction was very strong everywhere, but it was even closer to the colder regions. of the Earth, near the polar oceans, in the warmer tropical oceans ".
It's logical, he says. Animals that live near the equator can migrate to the poles to find colder water, but those who already live in oxygen-rich cold waters near the poles have very little space to run.
Deutsch says that experience is a window to the future – even to the present: marine species are already migrating. And for Deutsch, this migration seems familiar. "Today we see the reactions of marine species to these changes that resemble what we think happened at the end of the Permian," he says.
The Smithsonian exhibition makes explicit reference to the threat of climate change caused by humans; He has also received funding from industrialist David Koch, known for his support of groups challenging the scientific consensus on climate change.
Wing, the curator, explains that making the connection between the Great Dying and what is happening now is a message that needs to be heard. "We have gone beyond our own history," he said of the human race. "Because we are so powerful, we are now both a geological force and a human force."
A force that changes the conditions of life on the planet.
[ad_2]
Source link