The worst-case scenario in global warming could cause a mass die-off in marine species.
If the planet continues to warm at current rates, by the end of the century as many as 90% of marine species will be at risk of going extinct.
This stark warning comes from a team of scientists who examined some 25,000 species, including fish, marine plants, bacteria and protozoans, which live within a depth of 100 meters in the world’s oceans.
Based on the the worst-case scenario whereby unchecked carbon emissions carry on raising global atmospheric temperatures by between 3 degrees Celsius and 5 degrees Celsius, nearly nine out of 10 marine species near the surface will be at high or critical risk across 85% of their native habitats.
“One tenth of the ocean contains ecosystems where the aggregated climate risk, endemism and extinction threat of their constituent species are high,” the scientists explain in a study. “Climate change poses the greatest risk for exploited species in low-income countries with a high dependence on fisheries.”
Life on the planet has not experienced a die-off on this scale since the Permian Extinction 250 million years ago when 90% of species on Earth vanished.
That is the bad news. The good news is that we can still make a difference by lowering our emissions significantly in coming years and decades.If we can keep global temperature increases under 2 degrees Celsius, then the risk of extinction for all these species would diminish by 98%, the scientists say.
“Mitigating emissions reduces the risk for virtually all species (98.2%), enhances ecosystem stability and disproportionately benefits food-insecure populations in low-income countries,” they write.
Climate change is affecting almost all the creatures living near the surface in the world’s oceans, but larger predators are at more at risk than smaller predators. Similarly, fish species that are heavily fished by humans are also at greater risk because they have to grapple not only with a changing climate but with predation by humans as well.
At the lowest risk among fish are small, short-lived, fast-breeding species, the scientists say.