The largest mass extinction in history was caused by global warming?
Rapid global warming has caused the largest extinction in Earth’s history, killing off most of the planet’s marine and terrestrial animals, scientists say. A mass extinction, known as the Permian extinction, wiped out 96 percent of the Earth’s. Marine species and more than two-thirds of terrestrial species.
Permian extinction, referred to roalso referred to as „mothers of the great extinctions”, took place around 250 millionoyears ago. Long before the appearance of the dinosaurow, the planet was home to plants and animals thatore were mostly culled after a series of massive volcanic eruptions in Siberia.
Sediment researchoin the sea and fossils of ancient creatures from the seafloor show that this event was the biggest cataclysm that ever occurred on Earth. The fossil record shows a thriving and zroThe diversified marine ecosystem, whichory suddenly collapsed. .
According to scientistow from the University of Washington and Stanford University, about 96 percent of the species of theoin the sea was annihilated during the Great Extinction. The same fate has befallen more than two-thirds of the species ofoin terrestrial. The cataclysm was so severe that it destroyed most of the planet’s trees, insects, plants and even microbes.
There are at least a few theories as to the cause of the cataclysm, such as the impact of a giant asteroid, but U.S. scientists say rising temperatures are responsible. Analyses by scientistsow were published in the pages of the journal „Science”.
Scientists used paleoceanographic records and laboratory data and created a model to analyze changes in the animals’ metabolism and conditionsoIn oceanic and climatic. The results of the study indicate that the mass extinction in the Permian period oceans was caused by global warming, ktore deprived sea creatures of the ability to breathe. As temperatures rose and the metabolism of marine animals accelerated, warmer waters were unable to hold enough oxygen.
– For the first time, we have made a prediction about what caused the extinctions. This can be directly verified from the fossil record, allowing us to roalso predict the causes of future extinctions, said the paper’s first author Justin Penn of the University of Washington.
The climate model developed by the researchers takes into account oThe early configuration of Earth’s continentsow, when the land masses were combined to form a supercontinent called Pangea. Before ongoing volcanic eruptions in what is now Siberia spewed huge amounts of ash into the atmosphereow and gasow, the oceans had temperatures and oxygen levels similar to those of today. Then the researchers, in a computer model developed, gradually raised the concentration of gasoin greenhouse gases to levels thatory caused a temperature increase of about 10 deg. Celsius.
In such a model, the oceans lost about 80 percent of the. oxygen, and about half of the areaoin the marine depths became completely devoid of it. Scientists are convinced that this warming was caused by a huge jump in emissions of gasoin greenhouse gases, potentially caused by volcanic activity.
Scientists have analyzed the impact of such conditionsoin the oceans for 60 wspomodern marine organisms – crustaceans, fish or corals. Analyses have shown that the tolerance wspohe modern animals’ response to high temperatures and low oxygen levels is similar to Permian animals because they evolved under similar environmental conditions.
Scientists then combined the individual characteristics of the speciesoin with climate simulations to predict the geography of extinctions. – Very few organismoin the sea have remained in the same habitats, in which theorych lived. Most migrated or died, said Curtis Deutsch of the University of Washington, a cooroutor of research.
The computer model indicates that the greenhouse conditions and the decrease in the level of theoin oxygen hit organisms living closer to the pole hardestoin, although many speciesoin living in the tropics row also became extinct. This seems to be confirmed by an analysis of the fossil distribution made by Jonathan Payne’a and Erik Sperling of Stanford University. The researchers checked the archive of published collectionsow. Fossil records show where species lived before extinction. Their distribution confirms that species far from rownika suffered the most during this event.
– The signature of the extinction mechanism – climate warming and oxygen loss – is this geographic patternor, ktory is predicted by the model and subsequently confirmed in the distribution of fossils found, Penn said.
The study builds on earlier work by Deutsch showing that when the oceans are warm, the metabolism of marine animals speeds up, meaning they require more oxygen, while warmer water has less of it. This earlier study shows how warmer oceans cause animals to migrate out of the regionoin tropical.
– Because the metabolism of the organismoin the tropics was already adapted to warmer conditionsow and lower oxygen levels, they may have moved away from the tropicsoin and find the same conditions. But if an organism was adapted to a cold, oxygen-rich environment, these conditions ceased to exist – emphasized Deutsch.
Warming leading to insufficient oxygen explains more than half of the loss of romarine diversity. The authors say that other changes, such as acidification in theod probably acted as additional causes. The situation in poThe late Permian – increasing amount of gasoin greenhouse gases in the atmosphere, whichore causing rising temperatures on Earth – is similar to today’s.
Over the past century, the world has warmed by about 1 st. C. due to the release of gasoin greenhouse gases from burning fossil fuels such as coal, oil and gas. This warming is already causing heat wavesow, floods and fireow around the world, but scientists warn that temperature increases could reach 3 degrees Celsius. C. or more by the end of the century, unless there is an immediate, dramatic reduction in the.
At the same time, species on Earth are undergoing what someoexperts have named "shostim of the great extinction", and the reason is habitat loss, poaching, pollution and climate change.
– It scares me to think that we are on a trajectory similar to the Permian. Looks like we won’t warm up by about 10 st. C. and we do not lose this roBiodiversity. But even half of that, will be something to be very worried about. The size of the lesions, whichos we are currently experiencing is quite large – admitted Penn.
– When we get to 3-4 degrees of warming, much of the life in the ocean will be in serious trouble. Mooutright, there are big implications for human dominance on Earth – Deutsch stated, and added that the only way to avoid this is to reduce gas emissionsoin the greenhouse, given that there is no viable way to mitigate the impact of climate change in the oceans through other meansow.
Sourceobackground: EurekAlert!, The Guardian, fot. Justin Penn and Curtis Deutsch/University of Washington