New peak in carbon levels is bad news for the ocean

Corals in the Maldives suffering massive bleaching from heat stress in May 2016. (Keystone/The Ocean Agency/XL Catlin Seaview Survey via AP)

As the world celebrates World Ocean Day, a new high in levels of carbon dioxide in the air will have damaging effects on marine life.

Levels of carbon dioxide concentration in the atmosphere rose to record highs in May, causing a “serious impact on oceans”, the World Meteorological Organisation (WMO) said on Tuesday.

The Mauna Loa Observatory in Hawaii recorded a monthly average of 419.13 parts per million (ppm), a rise from 417.31 ppm in May 2020. Carbon dioxide is one of the key greenhouse gases emitted through human activities, primarily from burning fossil fuels. It is a major driver of global warming, contributing to more extreme weather events, ice melting, sea level rise and ocean acidification.

“The Mauna Loa figure is indicative of where we're heading, and that is very clearly in the wrong direction,” said WMO’s media officer Clare Nullis at a press briefing.

This news comes on the day the world celebrates World Ocean Day. Oceans absorb 23 per cent of carbon dioxide in the air, helping regulate the climate. This uptake also causes pH levels in the water to drop and acidity levels to rise.

Higher concentrations of CO2 means a more acidic ocean, reducing the ocean’s capacity to act as a carbon sink and keep the globe from heating further. Oceans also absorb roughly 90 per cent of the excess heat, increasing the frequency of marine heat waves.

The rapid rise in temperature and acidic levels are harming certain marine species such as corals, making it harder for them to survive and adapt. This is a threat to the livelihood of the millions of people that depend on oceans for food and work.

Temporary fall in emissions due to Covid. Last year carbon emissions took a historical plunge of 2.3bn tonnes or 6.4 per cent. While Covid-related lockdowns and restrictions momentarily hit the brakes on emissions, it was “just a temporary blip in the landscape” and won’t have a lasting impact, Nullis explained.

Emissions refer to the particles and gases released into the air, while concentration levels represent what is left after some of those emissions are absorbed by plants, oceans and land. Carbon dioxide can remain in the atmosphere for some 300 to 1,000 years, having lasting impacts for future generations.

For concentration levels to decline, the world would have to stop emitting as much CO2 for a longer period of time than a few months. Otherwise, it will continue to pile up in the atmosphere and feed into the seemingly endless loop of global warming.

Leaders from developed nations are expected to focus on the climate crisis and Covid at the upcoming G7 summit this weekend in Cornwall, UK, as the group meets in person for the first time after almost two years.