June 20, 2025 — The ocean is turning greener at the poles and bluer at the equator, and researchers say the small but mighty change in color spells danger, and fisheries will likely take the hit.
A tracked increase in vegetation cover, also known as greening, has been consistently recorded on land by scientists since the 1990s — meaning the average leaf cover across the planet’s surface has grown steadily, likely due to rising temperatures.
Using satellite images, the phenomenon has also been seen in the ocean, but inconsistent data on chlorophyll production thanks to the ocean’s sheer depth means studying greening rates sea-side is harder.
From 2003 to 2022, NASA satellite MODIS-Aqua traveled the entire Earth every two days, measuring light wavelength and gathering data nonstop.
Researchers at Duke University in Durham, North Carolina, conducted an ocean greening analysis, published June 19 in the journal Science, on the data in search of changes in the amount of chlorophyll, which signals the presence of aquatic ecosystem fundamental phytoplankton.