A study has revealed how ocean ecosystems, particularly through the mechanisms of the biological carbon pump (BCP), play a pivotal role in regulating atmospheric carbon dioxide (CO2) levels, carrying significant implications for climate change mitigation strategies. Published on March 5, 2025, this groundbreaking research utilizes the Norwegian Earth System Model (NorESM2), demonstrating how the removal of marine biological processes could lead to drastic increases in atmospheric CO2 and surface temperatures.
Oceans are often seen as the Earth's lungs, absorbing vast amounts of CO2 from the atmosphere and playing an indispensable role as climate regulators. Through the BCP, marine phytoplankton convert dissolved inorganic carbon (DIC) to organic matter, which sinks to the ocean depths, effectively sequestering carbon. The new study explores the hypothesis of how removing this biological process would alter the Earth’s carbon dynamics and exacerbate climate change.
This research focuses on the impacts across three different emissions scenarios, from high emissions (SSP5-8.5) to strong mitigation (SSP1-2.6), assessing future trajectories for atmospheric CO2 levels. Simulations without marine life indicated more than 50% higher atmospheric CO2 concentrations, equaling about 163 parts per million (ppm) compared to scenarios with ocean biology. Such changes correlate with significant increases in global surface temperatures, proposed to rise by 1.6 °C without the biological processes to keep CO2 levels balanced.
During the research's 2000-year spin-up period, the abiotic ocean—which lacked biological carbon uptake—released roughly 730 Pg C, with about 345 Pg C being absorbed by land ecosystems. This dynamic not only changes the physics of carbon cycling but also reflects how critically dependent the atmospheric CO2 concentrations are on the interactions between ocean biology and terrestrial ecosystems.
The findings from the study highlight alarming trends for the future. For projections running from 1850 to 2100, atmospheric CO2 levels are observed to escalate significantly higher under the abiotic conditions—an increase to 1433 ppm by 2100—compared to 1061 ppm with the biological systems intact. This stark difference emphasizes how, without ocean life, 68% to 83% of fossil fuel emissions would remain trapped within the atmosphere by the end of the century, effectively amplifying climate change beyond current models and expectations.
Such predictions hint at severe public health, environmental, and economic repercussions. This research demonstrates how the BCP not only moderates global warming today but also strengthens required curtailments on carbon emissions. Without biological assistance from marine life, the situation would worsen drastically, lending urgency to the need for integrated marine conservation efforts to safeguard these ecosystems.
The research team underscored the biological carbon pump's relevance, stating, "The removal of BCP leads to more than 50% (163 ppm) higher atmospheric CO2 and a 1.6 °C warmer surface temperature.” This new perspective serves to realign strategies for addressing climate change, advocating for ambitious policies aimed at protecting and sustaining marine wildlife and habitats.
By emphasizing the interplay between the reductions of marine biological systems and atmospheric conditions, researchers present findings pivotal for future climate modeling, reinforcing calls for greater investigation and prioritization of oceanic health within climate policies—an area increasingly acknowledged as fundamental to managing carbon emissions and ensuring environmental balance.
The authors conclude with the recommendation for enhanced monitoring and research efforts to assess the full scope of marine ecosystems on carbon dynamics. Moving forward, this study acts as both a warning and invitation to policymakers, researchers, and the global community to acknowledge and preserve the delicate wording of our oceans and their indispensable role as climatic regulators.