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[H.Eco Forum] Protecting the oceans and tackling climate change ‘go hand in hand’

Nam Sung-hyun, a School of Earth and Environmental Sciences professor at Seoul National University
Nam Sung-hyun, a School of Earth and Environmental Sciences professor at Seoul National University

Protecting the ocean environment is more important than people usually think, according to Nam Sung-hyun, a School of Earth and Environmental Sciences professor at Seoul National University.

Nam said the oceans work as massive carbon sinks and also absorb most of the solar energy reaching the Earth. Protecting the oceans and marine ecosystems is thus intimately involved in maintaining the Earth’s climate change resilience, Nam said in an email interview with The Korea Herald.

“More than 90 percent of the excess heat from human-caused global warming has been absorbed by the oceans,” Nam said. The amount of heat energy annually absorbed by the oceans is equivalent to the heat energy generated by detonating four atomic bombs, such as those dropped in the Japanese city of Hiroshima, according to Nam.

Oceans, replete with marine plants and animals, can retain a significant amount of carbon dioxide from the atmosphere, Nam said.

According to a report released by the United Nations Educational, Scientific and Cultural Organization, without oceans, atmospheric CO2 levels would have been at a whopping 600 parts per million, about 50 percent higher than the 410 ppm recorded in 2019, going well above the agreed target of limiting global warming to 2 degrees Celsius.

A potential danger is that oceans’ carbon sequestration ability -- being able to capture and store atmospheric carbon dioxide -- can go off balance if no preventive action is taken to protect the ocean environment, Nam said.

Nam said the increase in greenhouse gas emissions and the temperature of the atmosphere can cause modifications of the chemical properties of ocean water.

CO2 emissions, in particular, tend to acidify oceans when they dissolve in seawater, making it difficult for marine species and habitats to survive, affecting marine biodiversity. With damaged marine habitats, the ocean’s capacity to absorb CO2 too decreases.

“To recover the ocean’s capacity to absorb CO2, it is important to put efforts to keep the marine habitats healthy,” Nam said.

Nam stressed that reducing carbon emissions and protecting the ocean environments are intimately involved, and efforts to in both areas should go hand-in-hand.

“It is important to reduce carbon emissions. But, it is also equally important to protect marine ecosystems so that the Earth can maintain its carbon sequestration ability,” Nam said.

The tipping point regarding climate change is not different from the tipping point for oceans, Nam added.

Nam quoted an Intergovernmental Panel on Climate Change report, which warned that an increase of 1.5 degrees Celsius could reduce coral reefs by 70-90 percent, while more than 99 percent would be lost with 2 degrees Celsius.

When asked whether people are paying enough attention to protecting the oceans, compared to climate change, Nam was doubtful.

“The ocean had remained relatively inaccessible, perhaps less accessible than outer space where billionaires started space travel last year,” Nam said.

But with the advent of new technologies, humans now have better access to the oceans. Luckily, people are slowly beginning to take action in protecting marine habitats, he added.

Nam pointed to the Decade of Ocean Science for Sustainable Development, proclaimed by the United Nations, as a major step that would help us better understand the oceans and how people can ensure its sustainable development.

The decade, running between 2021 and 2030, was earmarked to ensure that the global ocean community and experts respond to the deteriorating global marine environment in a timely manner.

“During the decade designated by the UN, (we) should increase (our) scientific knowledge regarding the oceans and change the way to use the oceans in to more sustainable ones,” Nam said.

Nam also mentioned of the “30 by 30 target,” or the Global Ocean Alliance that aims to protect 30 percent of global land and at least 30 percent of the global ocean by 2030.

South Korea too has endorsed the target and is a member of the alliance, Nam said.

“(We) are living in a country located in a peninsula surrounded by the ocean on three sides,” Nam said. “We should realize the importance of the oceans in our lives, and the country should support activities that can protect and restore the ocean environment.”

By Shim Woo-hyun (
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