Ocean Warming Spells Disaster for Marine Ecosystems

Ocean Warming Spells Disaster for Marine Ecosystems

As global warming increases, oceans are absorbing most of the heat generated by greenhouse gas emissions because they are the world's largest carbon sinks. In 2014, 50% of the global ocean surface recorded extreme heat -- a figure that rose to 57% by 2019. According to a recent study, scientists say 2014 marks the year when extreme heat in oceans passed the "point of no return."

This warming has resulted in catastrophic consequences for marine ecosystems all over the world, including coral reefs in Australia and fisheries along the US Atlantic coast. Only 2% of coral in the Great Barrier Reef has escaped bleaching events, and kelp forests in California are disappearing entirely. These events not only signify biodiversity loss, but they are contributing to trophic cascades that will indirectly affect other species' survival.

Climate Change: a triple threat for the ocean (Source: IPCC, 2019: Special Report on the Ocean and Cryosphere in a Changing Climate (SROCC))

CBS: Global warming will be "catastrophic" for coral reefs, study finds, February 3, 2022.

Why this Matters

Marine ecosystems, such as coral reefs and fisheries, are not only important for community health and biodiversity, they are vital to both humans and the economy. Currently the Great Barrier Reef supports over 64,000 tourism jobs and generates A$6.4 billion for the Australian economy. Human livelihoods are intricately bound to the health of the ocean and cannot afford to have it destroyed.

"Any discussion of climate change that doesn't begin and end with the ocean probably needs to be reframed," said Kyle Van Houtan, the co-author of a paper mapping historical marine heat extremes. "It's 97% of the water on our planet. It generates the primary source of protein for two to three billion people every day. It provides medicine and good stable jobs."

Similarly Mark Eakin, the former director of the NOAA's Coral Reef Watch program makes the following comparison: "the loss of coral reefs due to the warming oceans is like wiping out entire states’ ability to grow grain." Adding, "Losing coral reefs will result in widespread hunger and political destabilization. This is why military leaders have identified the climate crisis as a threat multiplier, increasing the risk of societal meltdown and radicalization in many of the poorer countries of the globe."

Deutsche Bank: Protecting our oceans - towards a sustainable 'Blue Economy', July 6, 2021.

UN SDGAction: Dive into blue economy with Dona Bertarelli, the fastest woman to have sailed around the world, October 1, 2020.

Can Coral Reefs Survive Ocean Warming?

Coral reefs have a very narrow temperature range that they can survive in, which is bad news for them in a rapidly warming ocean. Reefs are widely regarded and predicted to be the first major ecosystem to disappear due to global warming and already over half of them have died in the last 30 years. However hopeless this may seem, new studies have found heat-resistant coral capable of living far above their temperature range, which could revitalize some reef ecosystems. Additionally, there was a reef discovered off the coast of Tahiti that was untouched by a bleaching event due to its unusual depth. These discoveries, combined with technological advancements to nurse coral reef ecosystems back to health, could aid in better ocean management tactics.

BBC: Pristine coral reef discovered off the coast of Tahiti, January 20, 2022.