More than half of the world’s oceans have developed a green hue in the past two decadesaccording to a study.

THE color change not so obvious to the human eye, but NASA satellite equipment has confirmed that over 56% of the world’s oceansa vast area larger than the total landmass of the Earth, it has become greener.

Measurements of ocean surface color made by satellite the last 20 years, revealed a global explosion in the growth of phytoplankton and plant-like microbes are common near the surface of the oceans.

While many of these microscopic organismsincluding green algae, they absorb carbon dioxide as they collect solar energytheir population explosion has contributed to suffocating “dead zones” by depleting oxygen globally.

“To see it actually happen, it’s not surprising, but it’s scary”according to study co-author Stephanie Dutkiewicz, a senior research scientist at the Massachusetts Institute of Technology (MIT).

These changes”he said, “are consistent with human-induced changes in our climate.”

The MIT team, in collaboration with the UK National Oceanography Centreanalyzed decades of ocean color data collected by MRI (MODIS) on NASA’s Aqua satellite.

The color data, collected from low Earth orbit, showed that the warmer tropical oceans near the equator have become the most consistently and permanently green over time.

A growth in phytoplankton, the foundation of the marine food chain which helps to conserve krill, fish, seabirds and marine mammals, can under normal circumstances be interpreted as a sign of ocean ‘health’.

But the overgrowth and oxygen absorption created by large masses of these microbes is associated with an increase in dead zones of the oceans and mass sea migrations for over a decade.

“I’ve been dealing with simulations that have been telling me for years that these changes in the color of the oceans would occur”Dutkiewicz said.

“Well, we hope people take this situation seriously.”


Greening of oceans discovered by researchers’ analysis of NASA’s MODIS-Aqua data from July 2002 to June 2022, published today in Nature journal.

And it seems that the greening twice more than expected.

The result, they said, is that this the greening cannot be explained by any natural, seasonal or year-to-year variations and variations in phytoplankton blooms alone.

“This situation shows that how human activities affect life on Earth over a vast spatial extent and the biosphere in general,” says study lead author BB Cael, of the UK’s National Oceanography Center in Southampton.

The researchers monitored seven wavelengths of colored light from the ocean surface using the MODIS system on NASA’s Aqua satellite.

Although the ocean appears uniformly blue to the naked eye, its true color contains a mixture of these wavelengths ranging from blue and green to red. Of course, some are more or less intense than others.

Cael and his team conducted a statistical analysis using all seven wavelengths measured by the Aqua satellite rather than just the two commonly used to measure changes in the green pigment chlorophyll from phytoplankton activity.

Cael’s team was able to compare these results with a prediction model that Dutkiewicz built at MIT in 2019.

Dutkiewicz’s model simulated changes in ocean color based on two scenarios: one with extra greenhouse gases in the atmosphere and another without it.

The greenhouse gas model predicted that, within 20 years, about 50% of the ocean surface will be more green.

“The ecosystem is changing, even if it’s hard to say exactly how”Cael told Vice.

“These color changes may indicate a shift to smaller or larger plankton sizemore or less predators or prey, different types of plankton that affect carbon storage or fisheries differently, among other things.”