Twice as many ocean-borne species have experienced local extinctions due to climate change than land-based ones, a new study reports.

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They may be hidden from our sight, but ocean dwellers are also suffering from climate change. In fact, says a new study led by researchers at Rutgers University-New Brunswick, they might be carrying the brunt of it. The rate of climate-change-induced extirpation in the oceans is double that seen on land, the paper explains. In addition to destabilizing marine environments, this may also significantly impact communities that rely on fish and shellfish for food or finance.

A thing of the deep

“We find that, globally, marine species are being eliminated from their habitats by warming temperatures twice as often as land species,” said lead author Malin Pinsky, an associate professor in the Department of Ecology, Evolution, and Natural Resources at Rutgers University-New Brunswick.

“The findings suggest that new conservation efforts will be needed if the ocean is going to continue supporting human well-being, nutrition, and economic activity.”

The study is the first to compare cold-blooded marine and land species’ sensitivity to a warming climate, as well as their ability to find shelter from heat in their natural habitats, the authors write. It included data (recorded in studies around the world) on nearly 400 different species including fish, reptiles, and spiders. The study notes that ancient extinctions have often been concentrated at specific latitudes and in specific ecosystems when the climate changed rapidly. Future warming is likely to trigger the loss of more marine species from local habitats and more species turnover in the ocean.

The team calculated safe conditions for 88 marine and 294 land species, as well as the coolest temperatures they could expect, in their natural habitats, during the hottest months of the year. On average, marine species are more likely to live in temperature conditions that are on the edge of dangerous. They also can’t seek shelter from the heat in forests, underground, or in shaded areas like land-based animals can — which further compounds their woes.

Such findings are particularly troubling as they showcase how fragile marine species can be in the face of climate change. And, it needn’t be whole species that goes extinct for the damage to mount — the team says that even the loss of local populations can deplete a species’ genetic diversity and have cascading impacts on the ecosystems that benefit human society.

“Understanding which species and ecosystems will be most severely affected by warming as climate change advances is important for guiding conservation and management,” the study says.

The paper ” Greater vulnerability to warming of marine versus terrestrial ectotherms” has been published in the journal Nature.