Scientists Warn New Ocean Discovery Could Worsen Climate Change

By: Georgia | Published: Jul 10, 2024

Recent studies have shown that as climate change progresses, the ocean’s overturning circulation is expected to weaken significantly. 

This slowing circulation is predicted to reduce the ocean’s ability to absorb carbon dioxide from the atmosphere, which could exacerbate global warming.

Balancing Carbon: The Ocean's Role

Although the ocean’s circulation is slowing, this should also mean less carbon is brought up from the deep ocean, which could have been released back into the atmosphere. 

Close-up of white sea foam on a sandy beach, highlighting the texture of sand and bubbles

Source: KAL VISUALS/Unsplash

Jonathan Lauderdale, a research scientist at MIT, explains, “The ocean should maintain its role in reducing carbon emissions from the atmosphere, if at a slower pace.”


MIT Study Challenges Previous Beliefs

A recent study published in Nature Communications by an MIT researcher suggests that scientists may need to rethink the relationship between ocean circulation and its ability to store carbon long-term. 

A serene view of calm ocean water with a gentle ripple, showcasing the tranquility of the sea

Source: Matt Hardy/Unsplash

As the circulation weakens, it could release more carbon from the deep ocean into the atmosphere.

Intricate Ocean Feedback Loops Revealed

The study highlights a complex feedback loop involving the ocean’s iron, upwelling carbon, nutrients, surface microorganisms, and a class of molecules known as “ligands.” 

A breathtaking sunset view over a tropical beach with gentle waves washing ashore and clouds scattered in the colorful sky

Source: Sean Oulashin/Unsplash

These interactions could increase the amount of carbon that the ocean releases back into the atmosphere when the circulation slows.

Fundamental Shift in Understanding

“By isolating the impact of this feedback, we see a fundamentally different relationship between ocean circulation and atmospheric carbon levels, with implications for the climate,” Lauderdale states

A powerful, curling ocean wave captured at the moment of breaking

Source: Matt Paul Catalano/Unsplash

This indicates a significant shift in how we understand the ocean’s role in climate dynamics.

Rethinking Ocean Carbon Storage

Lauderdale further notes, “What we thought is going on in the ocean is completely overturned.” 

Underwater view of a vibrant coral reef bathed in sunlight, with small fish swimming above and clear blue water surrounding the scene

Source: Marek Okon/Unsplash

The findings suggest that we cannot rely on the ocean to indefinitely store carbon in the deep ocean in response to changes in circulation.


The Role of Iron in Ocean Chemistry

Iron is crucial for phytoplankton growth, which in turn influences how much carbon dioxide they can sequester through photosynthesis. 

A microscopic image showing various forms of phytoplankton with intricate details, including spiral and straight shapes with a greenish tint, visible against a grey background

Source: Wikimedia Commons

However, iron’s effectiveness depends on its interaction with ligands, which help keep it in a soluble form accessible to phytoplankton.


Complex Dynamics of Ocean Nutrients

The 2020 study led by Lauderdale developed a simple “box” model to represent the ocean’s complex nutrient dynamics. 

Close-up view of turbulent, frothy ocean water creating patterns of white foam, indicative of the ocean's dynamic surface activity

Source: Christoffer Engström/Unsplash

This model demonstrated that even increasing iron in certain regions doesn’t significantly boost global phytoplankton growth due to ligand limitations.


A Surprising Discovery in Ocean Modeling

While modifying his box model, Lauderdale discovered that decreasing ocean circulation strength was unexpectedly linked to higher atmospheric CO2 levels.

A tranquil ocean scene at sunset with a kitesurfer in the distance, waves gently rolling in

Source: Earth/Unsplash

This is a direct contradiction to previous assumptions held since the 1980s.


Revising Oceanic Models

When Lauderdale adjusted the model to fix ligand concentrations, the results aligned with traditional expectations: weaker circulation resulted in lower atmospheric CO2. 

Aerial view of a serene tropical cove with turquoise waters, white sandy beaches, and lush green islets surrounded by a boat leaving a wake

Source: Denys Nevozhai/Unsplash

This finding challenges the variability of ligand concentrations in different ocean regions.


Validating Findings with Real-World Data

Lauderdale’s results were later supported by data from the GEOTRACES study, which measures trace elements and isotopes across oceans and confirmed that ligand concentrations vary regionally.

Close-up view of a massive ocean wave forming a perfect tunnel

Source: Jeremy Bishop/Unsplash

This makes the surprising new model outcomes more credible.


Implications for Climate Action

The research demonstrates the complexity of ocean processes and their impact on climate. Lauderdale emphasizes, “We must be proactive in cutting emissions now, rather than relying on these natural processes to buy us time to mitigate climate change.” 

Aerial view of an industrial area emitting large amounts of steam or smoke, captured during sunset with a golden hue over the landscape

Source: Marcin Jozwiak/Unsplash

This statement reflects the urgent need to address emissions directly.