If human greenhouse gas emissions continue to increase, according to New study Released Thursday, nearly a third of all marine animals could disappear within 300 years.
The findings, published in the journal Science, reveal a possible mass extinction looming beneath the waves. The oceans have absorbed a third of the carbon and 90 percent of the excess heat generated by humans, but their vast breadth and forbidden depths mean scientists are only just beginning to understand what creatures there are up to.
However, the study by Princeton University earth scientists Justin Penn and Curtis Deutsch also underscores how much marine life can still be saved. If the world takes rapid action to reduce fossil fuel use and restore degraded ecosystems, the researchers say, it could reduce potential extinctions by 70 percent.
“This is a landmark paper,” said Malin Pinsky, a Rutgers University biologist who did not contribute to the research, in an interview. “If we’re not careful, we’re headed toward a future that I think for all of us right now is going to look absolutely hell. … It’s a very important wake-up call.”
The world has already warmed by more than 1°C (1.8 degrees Fahrenheit) since the pre-industrial era, and last year The oceans contained more thermal energy More than at any time since record-keeping began six decades ago.
Increasing ocean temperatures are shifting the boundaries of comfort zones for marine creatures. Many are fleeing north in search of cooler waters, causing an “eradication” – or local disappearance – of once-common species.
Arctic creatures that can survive only in the coldest conditions may soon find themselves with nowhere to go. Species that cannot move easily in search of new habitats, such as fish that depend on certain coastal wetlands or seafloor geological formations, are more likely to become extinct.
Using climate models that predict species behavior based on simulated species of organisms, Deutsch and Benn found that the number of eradications, or the local disappearance of specific species, increases by about 10 percent with every one degree Celsius of warming.
The researchers tested their models using them to simulate a mass extinction at the end of the Permian, when catastrophic warming from volcanic eruptions wiped out nearly 90% of life on Earth. Because the models successfully replicated the events of 250 million years, the scientists were confident in their predictions of what might happen 300 years in the future.
Ben and Deutsch’s research revealed that most animals cannot afford to lose more than 50 percent of their habitat – after that number, the species falls into irreversible decline. In the worst emissions scenarios, the losses would be on par with the five worst mass extinctions in Earth’s history.
These changes are already beginning to appear. In the 1980s, a heat wave in the Pacific Ocean wiped out a small silverfish called Galapagos girl of the waters off Central and South America. a hot spot Along the Uruguayan coast it has led to the mass deaths of oysters and large-scale shifts in the fishing of fishermen. Japanese salmon fisheries have I retreated Sea ice is receding and warmer, nutrient-depleted waters invade the area.
The danger of warming is exacerbated by the fact that hotter waters begin to lose dissolved oxygen – although higher temperatures speed up the metabolism of many marine organisms, so they need more oxygen to live.
The ocean contains one 60 percent of the oxygen in the atmosphere; Even less in warmer regions where water molecules are less able to prevent valuable oxygen from returning to the air. As global temperatures rise, this reservoir is retreating further.
Heating of the sea surface also splits the ocean into distinct layers, making it difficult for the warmer and oxygenated waters above to mix with the cooler depths. Scientists have Documented Expand “shadow zones” where oxygen levels are so low that most life cannot survive.
Deutsch, one of Deutsch, said the deoxygenation process poses one of the biggest climate threats to marine life Study co-authors. Most species can take a little extra energy to deal with higher temperatures or adapt to higher acidity. Some corals have even found ways to prevent calcium carbonate skeletons from eroding in acidic waters.
“But there is no price that organisms can pay for more oxygen,” Deutsch said. “They’re kind of stuck.”
This climate-related marine extinction is just one part of a broader biodiversity crisis sweeping the entire world. a recent report From the Intergovernmental Panel on Climate Change found that warming has already contributed to the disappearance of at least 400 species. a separate panel for the United Nations He found that about one million additional species are at risk of extinction as a result of overexploitation, habitat destruction, pollution, and other human disturbances in the natural world.
a Comprehensive new evaluation Published Wednesday in the journal Nature showed that more than 20 percent of reptile species can disappear. Turtles and crocodiles are the most vulnerable, and more than half of each group is at least at risk of extinction in the near future.
The consequences could be dire for societies that depend on reptiles for food, pest management, culture and other services.
The co-author said: “If we start spoiling ecosystems and the services they provide, it will have spillover effects Neil CoxDirector of the Biodiversity Assessment Unit at the International Union for Conservation of Nature. “I think the threats to biodiversity are as severe as climate change, we just underestimate them.”
However, the two crises are closely intertwined, adds Blair Hedges, an evolutionary biologist at Temple University and contributor to the assessment of reptiles. Climate change could accelerate the demise of populations already disturbed by habitat degradation or hunting. Ecosystems that lose key species may be less able to pull carbon from the atmosphere or be insulating against the effects of climate.
Researchers have highlighted the plight of the minor reptile Virgin Gorda, a thumb-sized reptile that dwells in moist pockets of soil on the hillsides of the Caribbean. The creation of national parks on the islands where the gecko is found has helped avoid habitat loss that would have wiped out the species. But its habitat is now drying up from climate change, raising the specter of extinction again.
“If you have multiple threats … working together, often even when you think one is under control, the other becomes more threatening,” Hedges said.
Although the danger to animals — and the humans who depend on them — is undoubtedly grave, Rutgers biologist Pinsky urged not to give in to despair.
In the analysis of science Who accompanied the Ben and Deutsch report, he and Rutgers ecologist Alexa Friedstone compared marine animals to the Canary Islands in a coal mine, alerting humanity to unseen forces — such as dangerous carbon dioxide build-up and oxygen loss in the ocean — that also threaten our ability to survive. . If people can take action to conserve ocean wildlife, we will end up saving ourselves.
It’s scary, but it also gives strength,” Pinsky told The Post.
He added, “What we do today and tomorrow and the rest of this year and next has really important consequences. This is not ‘once in a lifetime’ but perhaps ‘once in a lifetime’.”