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Unchecked emissions could kill 90 percent of marine species

A recent study led by Dalhousie University in Canada has found that, if greenhouse gases continue to be emitted at current rates, nearly 90 percent of all marine species could be at risk of extinction by the end of the century. Among the various species of animals, plants, chromists, bacteria, and protozoans examined, higher trophic species – particularly those that are harvested for food, including tunas, sharks, or pufferfish – had the highest risk of going extinct.

The researchers evaluated threats faced by almost 25,000 marine species which inhabit the upper 100 meters of oceans if greenhouse gas emissions continue to stay at high levels, under a “business as usual” scenario. The analysis revealed that almost 90 percent of these animals may be at high or critical risk of extinction by 2100, and will not be expected to survive in their current habitat across an average of 85 percent of their geographical distribution. In addition, the scientists found that about 10 percent of the ocean has areas of combined high climate risk and endemism (the state of a species being found in a single defined geographical location), which place further threats on a vast majority of ecosystems.

According to study lead author Daniel Boyce, an ecologist at Dalhousie University, these findings are “quite startling and very sobering,” providing clear evidence of the massive danger life on our planet faces if extraction of fossil fuels continues unmitigated. “I’d like to think that that’s an implausible scenario,” he said. “But nonetheless, it is the worst-case scenario. And when we evaluated that scenario, we found that there was a very grim picture for the climate risk for marine species.”

The threats were found to be higher for many species that are currently harvested for food in low-income countries highly dependent on fisheries. “There was a really striking pattern where the risk was systematically higher for nations that have a lower socioeconomic status, lower income nations that tend to be more dependent on fisheries and tend to have a lower food security, and overall nutritional status,” Professor Boyd explained.

These findings should lead to increased efforts to prioritize the conservation of vulnerable ecosystems by taking into account the susceptibility and adaptability of various species in climate management strategies. “It should provide a strong motivation for us to do everything that we can to mitigate our emissions and focus on avoiding that worst-case scenario,” he concluded.

The study is published in the journal Nature Climate Change.      

By Andrei Ionescu, Staff Writer  

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