Billions of Marine Organisms Participate in Earth’s Largest Migration, Impacting Carbon Levels
In this underwater photo taken on April 5, 2024, marine biologist Anne Hoggett snorkels to inspect and record bleached and dead coral around Lizard Island on the Great Barrier Reef, located 270 kilometres (167 miles) north of the city of Cairns. DAVID GRAY/AFP via Getty Images

Every evening, as the sun sets, a remarkable event unfolds in the ocean. Countless tiny creatures, like zooplankton and crustaceans, rise to the surface to eat microscopic algae before descending back into the depths at dawn.

This nightly migration is the largest of its kind on Earth and helps remove millions of tonnes of carbon from the atmosphere each year. Unfortunately, as the planet warms, scientists are increasingly worried that these natural processes are declining.

Nightly Migration of Ocean Creatures Plays Key Role in Carbon Absorption

In 2023, which was recorded as the hottest year ever, a global study showed a significant drop in carbon absorption by land. Researchers found that forests, plants and soil absorbed almost no carbon at all.

This alarming trend means that essential carbon sinks, which help absorb about 50% of human emissions, are failing. Additionally, the glaciers in Greenland and the Arctic are melting faster than expected, disrupting ocean currents like the Gulf Stream and further reducing the oceans' ability to absorb carbon.

Johan Rockström, director of the Potsdam Institute for Climate Impact Research, expressed his concern during New York Climate Week. He highlighted that nature has managed to balance the effects of human activity so far, but this balance is now reaching its breaking point.

The 2023 study also indicated that land ecosystems could return to their previous carbon absorption roles if droughts and wildfires do not occur frequently. However, with rising temperatures and extreme weather events, these ecosystems face new challenges.

The Congo Basin remains the only tropical rainforest effectively absorbing more carbon than it emits, unlike the Amazon, which is struggling with drought and deforestation. If current trends continue, soil emissions, the second-largest carbon reservoir, could rise by up to 40% by the end of the century.

Ecosystem Instability Poses Threat to Carbon Absorption and Climate Goals

Tim Lenton from Exeter University pointed out that unexpected responses from ecosystems challenge previous predictions, raising questions about their future as carbon sinks, according to The Guardian.

Despite ongoing research efforts, many climate models do not account for the significant carbon loss caused by wildfires or droughts. Andrew Watson from the University of Exeter warned that while models predict a gradual decline in carbon sinks, the reality may unfold much sooner.

As climate change continues to impact natural carbon sinks, the implications for countries striving to meet their climate goals become increasingly severe. Finland, for example, has seen its once-robust land sink disappear, threatening its carbon neutrality targets despite a 43% reduction in emissions.

Experts agree that it's crucial to protect existing carbon sinks and reduce emissions from fossil fuels. Professor Pierre Friedlingstein of Exeter University emphasized that relying solely on forests for carbon absorption is not a sustainable solution.

Without immediate action, the delicate balance of Earth's ecosystems could be irreparably disrupted, leaving future generations to face the consequences.