Climate change has shifted colour of over half of world's oceans: Study

economictimes.indiatimes.com:

Earth's total land expanse, has changed significantly over the last two decades and human-caused climate change is likely the driver, according to researchers. These colour changes, subtle to the human eye, cannot be explained by natural, year-to-year variability alone, the researchers from the Massachusetts Institute of Technology (MIT), US, and other institutes write in their paper published in the journal Nature. Ocean colour, a literal reflection of the life and materials in its waters, in regions near the equator was found to have steadily turned greener over time, indicating changes in the ecosystems within the surface oceans. The green colour of the ocean waters comes from the green pigment chlorophyll present in phytoplankton, the plant-like microbes abundant in upper ocean. Scientists are, therefore, keen to monitor phytoplankton to see their response to climate change. However, the authors of this study showed through previous studies that it would take 30 years of tracking chlorophyll changes before climate-change-driven trends would show, because natural, annual variations in chlorophyll would overwhelm those influenced by human activities. In a 2019 paper, study co-author Stephanie Dutkiewicz and her colleagues showed that monitoring other ocean colours, whose annual variations are much smaller than those of chlorophyll, would convey more clear signals of climate-change-driven changes and that they might even be apparent in 20 years, rather than 30.

Oceans are changing colour and climate change may be to blame

«It's worth looking at the whole spectrum, rather than just trying to estimate one number from bits of the spectrum,» said lead author B. B. Cael of the National Oceanography