Over the last two decades, more than half of the Earth’s oceans have undergone noticeable color shifts that cannot be explained by natural processes alone. Scientists attribute these changes largely to human activities, and they warn that such shifts can disturb marine food webs and ecosystem balance. This finding comes from a comprehensive study published in Nature.
A team from the Massachusetts Institute of Technology conducted their analysis using data from the Aqua satellite, covering 2002 through 2022. The satellite’s color sensing capabilities reveal changes invisible to the naked eye, enabling researchers to track subtle shifts in ocean color on a global scale.
The research highlights a trend toward greener tropical oceans near the equator during the past twenty years. This greening indicates an increased presence of phytoplankton, the microscopic, photosynthetic organisms that form the base of oceanic food chains. Phytoplankton support the survival of fish, seabirds, and marine mammals and also play a crucial role in carbon sequestration. When their abundance shifts, the entire marine community can feel the impact, and the ocean’s capacity to store carbon may also be affected.
To understand potential causes and consequences, the researchers integrated climate change models with atmospheric pollution scenarios. The models suggest that higher levels of greenhouse gases could alter the color of about half of the world’s oceans. While the exact implications of these color changes are still being explored, the study clearly points to human activity as a driving force behind the observed patterns.
The authors note a general disruption to the natural organization of marine ecosystems when ocean colors change. They warn that warming seas, driven by sustained greenhouse gas emissions, could amplify these disturbances in the years ahead, potentially reshaping nutrient cycles, habitat availability, and species interactions across vast marine regions.
In related developments, earlier research from China has identified film techniques that slow the melting of glaciers, underscoring the broad scientific effort to understand and mitigate climate-related changes affecting oceans and ice reserves alike.