A 2023 study led by the UK’s National Oceanography Centre has found a major shift in ocean colours across the globe. Using 20 years of NASA satellite data, researchers discovered that 56% of the world’s ocean surface has changed hue. The cause is likely climate change, affecting phytoplankton—the microscopic organisms that shape marine life and colour.

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• Over half of ocean surface (56%) changed colour in last 20 years
• Study led by B. B. Cael, published in Nature
• Used NASA Aqua satellite with MODIS instrument
• Ocean near equator turning greener; low-life zones getting bluer
• Colour change tied to phytoplankton distribution and health
• Greener waters = more phytoplankton; bluer = fewer organisms
• Norwegian Sea, North Atlantic saw chlorophyll rise 200–500% in Apr 2023
• West of Iberian Peninsula, sharp chlorophyll drop
• Mediterranean chlorophyll spiked 50–100% above normal by June 2023
• Changes invisible to naked eye, but clear in satellite data