OCEANS ARE OBSERVING MORE CARBON DIOXIDE (CO2) EMISSIONS

This is no secret that the world’s oceans play a crucial role in mitigating climate change by absorbing a significant portion of carbon dioxide (CO₂) emissions. Recent estimates suggest that the oceans absorb between 25 percent and 31 percent of annual CO₂ emissions.

Source: NOVA

It was broadcasted all over the world that current scientific studies have shown that the oceans are absorbing more CO2 than previously understood which is no doubt is encouraging. These discoveries focus on how the following oceanic processes contribute to absorbing more CO2:

PLANKTON BLOOM Source: ESA
  1. Plankton Growth: Phytoplankton growth depends on the availability of carbon dioxide, sunlight, and nutrients. Phytoplankton, like land plants, require nutrients such as nitrate, phosphate, silicate, and calcium at various levels depending on the species. Plankton growth refers to the increase in the population of plankton organisms, which are microscopic or small organisms that drift in the water. Plankton categorized into two main types:
    • Phytoplankton (plant-like plankton): These are microscopic algae that use photosynthesis to produce energy, forming the base of the aquatic food chain; and
    • Zooplankton (Animal-like Plankton): These organisms feed on phytoplankton or other smaller zooplankton.
  2. Ocean Currents: Ocean currents are the continuous, predictable, directional movement of seawater driven by gravity, wind (Coriolis Effect), and water density. Ocean currents are large-scale flows of seawater that move continuously through the world’s oceans. They play a crucial role in regulating the Earth’s climate, distributing heat, and facilitating the movement of nutrients and marine life. Ocean currents are driven by a combination of factors, including wind patterns, the Earth’s rotation, water temperature, and salinity differences, and the shape of the ocean basins. Type of Ocean Currents include:
    • Surface Currents;
    • Deep Ocean Currents (Thermohaline Circulation); and
    • Tidal Currents.
  3. Atmospheric Changes: Atmospheric changes refer to shifts or variations in the Earth’s atmosphere over time. These changes can be driven by natural processes or human activities and can impact weather patterns, climate, air quality, and ecosystems. Atmospheric changes can happen on various timescales, from daily fluctuations in weather to long-term shifts in global climate. Atmospheric changes, whether natural or human-induced, have wide-reaching impacts on the environment and human society. Understanding the drivers of these changes, their consequences, and the potential solutions is crucial for building a more sustainable future and mitigating the worst effects of climate change. Here are some key aspects of atmospheric changes:
    • Weather vs. Climate;
    • Natural Atmospheric Changes;
    • Human-Induced Atmospheric Changes;
    • Key Atmospheric Changes;
    • Impact of Atmospheric Changes; and
    • Mitigating Atmospheric Changes.
CHANGE IN ATMOSPHERE Source: European Space Agency

In the last 200-plus years since the industrial revolution began, the concentration of CO2 in the atmosphere has increased due to human actions which included burning fossil fuels (Coal, Oil, and Natural Gas), deforestation, agriculture, industrial processes, and waste management. During this time, the pH of surface ocean waters has fallen by 0.1 pH units. This might not sound like much, but the pH scale is logarithmic, so this change represents approximately a 30 percent increase in acidity. Here’s an explanation for what “pH’ stands for: pH is a scale that measures how acidic or basic (alkaline) a substance is. It ranges from 0 to 14:

  • pH 7 is neutral (like pure water);
  • A pH less than 7 indicates an acidic substance (like lemon juice or vinegar); and
  • A pH greater than 7 indicates a basic (alkaline) substance (like baking soda or soap).
Source: Science News Explores

The pH scale is logarithmic, meaning that each whole number change represents a tenfold difference in acidity or alkalinity. So, a substance with a pH of 4 is 10 times more acidic than one with a pH of 5.

In any case, the ocean generates 50 percent of the oxygen we need, absorbs 25 percent of all carbon dioxide emissions and captures 90 percent of the excess heat generated by these emissions. It is not just ‘the lungs of the planet’ but also its largest ‘carbon sink’ – a vital buffer against the impacts of climate change.

Source: wikipedia

Nevertheless, a significant part of this discovery revolves around the ocean’s biological pump, where marine organisms like phytoplankton capture carbon through photosynthesis and then transport it to deeper layers of the ocean when they die or are consumed. Some studies have suggested that warming oceans and changing climate conditions may lead to increased plankton activity in certain regions, helping the oceans absorb more CO2. Additionally, the “buffering” effect of the oceans, which allows them to hold more CO2 without drastic pH (Potential of Hydrogen) changes, has also been a focal point.

Source: Woods Hole Oceanographic Institute

The good news is that new research commissioned by the High Level Panel for a Sustainable Ocean Economy (Ocean Panel) shows that ocean-based climate solutions can deliver up to 35 percent of the annual greenhouse gas (GHG) emission cuts needed in 2050 to limit global temperature rise to 1.5 degrees C (2.7 degrees F) — the threshold scientists say it is necessary to avert the worst outcomes from climate change. This represents a significant increase from previous estimates, which put the ocean’s potential emissions reductions at around 21 percent of the total needed by 2050.

Source: University of Florida

The bad news is that in 2024, global carbon dioxide (CO₂) emissions reached a record high of approximately 41.6 billion tonnes, marking a 0.8 percent increase from the previous year.

Applying these percentages to the 2024 emissions data indicates that the oceans absorbed approximately 10.4 to 12.9 billion tonnes of CO₂ in 2024. This absorption capacity underscores the vital role oceans play in regulating the global climate system.

Source: NOAA

The new study – led by researchers from the University of Exeter’s Penryn Campus in Cornwall – used precision measurements to confirm that the temperature of the ocean skin does indeed aid carbon absorption.

Carried out in the Atlantic, the findings suggest this ocean absorbs about 7 percent more CO₂ each year than previously thought. It might sound small, but when applied across all oceans this additional carbon absorption is equivalent to one and half times the carbon captured by annual forest growth in the Amazon rainforest. Dr. Daniel Ford, lead author of the study said:

  • “Our findings provide measurements that confirm our theoretical understanding about CO₂ fluxes at the ocean surface.”

Dr Ian Ashton, also from the University of Exeter, said:

  • “This work is the culmination of many years of effort from an international team of scientists. The European Space Agency’s support for science was instrumental in putting together such a high-quality measurement campaign across an entire ocean.”

Dr Gavin Tilstone, from Plymouth Marine Laboratory (PML), said:

  • “This discovery highlights the intricacy of the ocean’s water column structure and how it can influence CO₂ draw-down from the atmosphere. Understanding these subtle mechanisms is crucial as we continue to refine our climate models and predictions. It underscores the ocean’s vital role in regulating the planet’s carbon cycle and climate.”
Greely, Ontario, Canada 3 February 2025