The Guardian reported that a new study published in the journal Science warned that global warming is drastically changing the ocean ecosystem and may trigger the worst mass extinction of marine species in tens of millions of years.
As temperatures rise and oxygen depletion worsen, scientists fear a resurgence of mass extinction mechanisms.
The burning of fossil fuels is causing global sea temperatures to rise steadily, oxygen levels in the ocean to drop, and the water to become more acidic as it absorbs carbon dioxide from the atmosphere.
The amount of ocean water completely depleted of oxygen, making it inhospitable to life, has tripled since the 1960s. Furthermore, due to ocean acidification, aquatic organisms such as clams, mussels, and shrimp have difficulty producing their shells properly.
The study shows that these changes indicate that Earth may be on the verge of a historic mass extinction. Researchers say the stress caused by rising temperatures and oxygen depletion is reminiscent of the mass extinction event at the end of the Permian period about 250 million years ago - a catastrophe known as the "Great Dying" that killed as much as 96% of the world's marine animals.
"Even if the magnitude of current species loss is different from the end-Permian mass extinction, the mechanisms of species loss are the same," said Justin Penn, a climate scientist at Princeton University and co-author of the study.
4% of marine species could become extinct under 2°C warming
"The future of marine life depends crucially on how we address greenhouse gases now," Payne said. "For the foreseeable future, the ocean faces two starkly different fates, one of which will leave it devoid of the rich life it currently possesses."
The study found that if the world continues to emit greenhouse gases without restraint, average temperatures will exceed 4°C above pre-industrial levels by the end of this century, potentially leading to truly catastrophic extinction events. As temperatures continue to rise, species extinction will reshape the marine ecosystem, with impacts that will last for centuries.
Even under a better-case warming scenario, the world will still lose a significant portion of its marine life. Even if governments implement their current climate pledges, this could still lead to a 2°C warming scenario, in which around 4% of the approximately 2 million marine species will become extinct.
资料来源: 环境资讯中心 (https://e-info.org.tw/node/233971)
