Business-as-usual carbon emissions would cause global warming that brings serious ocean acidification, death of corals and mangroves, scientists say

This article is more than 5 years old

This article is more than 5 years old

Time is rapidly running out for the world’s oceans and the creatures that live in them as the Earth’s climate continues to warm, say scientists.



Only “immediate and substantial” reductions in greenhouse gas emissions can hope to prevent “massive” impacts on marine ecosystems, warn the experts.

Researchers compared the fate of the oceans under two scenarios, one a “business-as-usual” approach and the other involving drastic cuts in emissions.

Their analysis showed that business-as-usual would have an enormous and “effectively irreversible” impact on ocean ecosystems and the services they provide, such as fisheries, by 2100.

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Even after curbing emissions of carbon dioxide (CO2) enough to prevent temperatures rising by more than 2C compared with pre-industrial levels, many marine ecosystems would still suffer significantly, they said.

The international team led by Dr Jean-Pierre Gattuso, from the Laboratoire d’Océanographie de Villefranche in France, wrote in the journal Science: “Impacts on key marine and coastal organisms, ecosystems, and services from anthropogenic (man-made) CO2 emissions are already detectable, and several will face high risk of impacts well before 2100, even with the stringent CO2 emissions scenario.

“These impacts are occurring across all latitudes and have become a global concern that spans the traditional north/south divide.”

Any new global climate agreement that fails to minimise the impact on oceans will be “incomplete and inadequate”, stressed the scientists.

The findings are intended to inform the forthcoming 2015 United Nations climate change conference in Paris.

By 2050, the loss of critical habitats such as coral reefs and mangroves was expected to contribute to “substantial declines” for tropical fisheries, on which many human communities depended, said the researchers. This was the case even under the 2C emission cutting scenario.

While Arctic fisheries may benefit from warmer temperatures at first, the scientists pointed out that this region was a “hot spot” of ocean acidification. It also contained communities that were highly reliant on the sea.

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The risk of impacts on mid-latitude fisheries was more variable but likely to “increase substantially” under the “business-as-usual” scenario.

Co-author Dr Rashid Sumaila, director of the Fisheries Economics Research Unit at University of British Columbia in Canada, said: “From looking at the surface of the ocean, you can’t tell much is changing. The oceans are closely tied to human systems and we’re putting communities at high risk.”

The research was based on experiments, field observations and computer simulations.