Climate Change Could Destroy 90% of Marine Life by 2100

Medscape Staff

November 07, 2022

Up to 90% of all marine life across the globe could face extinction by 2100 if drastic measures aren't taken to reduce greenhouse gases, according to an international team of researchers reporting in Nature Climate Change.

What to know:

  • Under the high greenhouse emissions currently being observed, global atmospheric temperatures will increase 3-5 °C in the next 80 years, and almost 90% of the estimated 25,000 marine species of fish, bacteria, plants, and protozoans face high or critical risk for extinction.

  • One tenth of the world's oceans contains ecosystems where the aggregated climate risk, endemism, and extinction threat of their constituent species are high.

  • Larger top predators are more at risk than are smaller predators, as are fish species in areas where they are heavily fished by humans, with small, short-lived species at the lowest risk of all.

  • Greenhouse gas emissions affect the world's climate in two ways: raising the temperature of the atmosphere by holding in heat and, in the case of CO2 emissions, making water more acidic.

  • Earth has not seen a die-off as great as these projections since the Great Dying 252 million years ago. But, if emissions are cut to the extent outlined by the Paris Climate Agreement, which would keep global temperature increases to below 2 °C, then the risk for extinction would be reduced by approximately 98%.

This is a summary of the article "A climate risk index for marine life" published in Nature Climate Change on August 22, 2022. The full article can be found on

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