Climate Change Altering Colour of Over 56% of the World's Oceans: Study | Weather.com - The Weather Channel

Climate Change Altering Colour of Over 56% of the World's Oceans: Study | Weather.com

Human-induced climate change has altered the colour of more than 56 per cent of the world's oceans in the last 20 years, according to a concerning study. The study, published in the journal Nature, reveals that tropical ocean regions near the equator have consistently become greener over time. This change in ocean colour suggests that ecosystems within the surface ocean are also undergoing transformations, as the colour of the ocean reflects the organisms and materials present in its waters.

Scientists, including researchers from the Massachusetts Institute of Technology (MIT) in the US and the National Oceanography Center in the UK, observed these shifts in ocean colour over the past two decades. They concluded that these changes cannot be solely attributed to natural year-to-year variability.

Although these alterations in colour may be subtle to the human eye, they have occurred across more than 56 per cent of the world's oceans—an area larger than the total landmass of Earth.

"I have been running simulations that have predicted these changes in ocean colour for years. To witness them occurring, in reality, is not surprising, but it is frightening. Moreover, these changes align with the man-made alterations to our climate," stated co-author Stephanie Dutkiewicz, senior research scientist in MIT's Department of Earth, Atmospheric and Planetary Sciences and the Center for Global Change Science.

Lead author BB Cael, from the National Oceanography Center in Southampton, UK, added, "This provides further evidence of the extensive impact of human activities on life on Earth. It represents another way in which humans are affecting the biosphere."

Previously, in order to gauge the impact of climate change on oceans, scientists primarily monitored phytoplankton—plant-like microorganisms abundant in the upper ocean that contain the green pigment chlorophyll and play a vital role in the marine food web and carbon dioxide capture and storage.

However, researchers realised that at least 30 years of continuous monitoring would be required to detect any climate change-driven trends. In the current study, Cael and the team analysed ocean colour measurements taken by the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Aqua satellite, which has been monitoring ocean colour for 21 years. MODIS captures measurements in seven visible wavelengths, including the two colours traditionally used by researchers to estimate chlorophyll levels.

The differences in colour detected by the satellite are too subtle for the human eye to discern. While much of the ocean appears blue to us, its true colour may contain a mix of subtler wavelengths, ranging from blue to green and even red.

Cael conducted a statistical analysis using all seven ocean colours measured by the satellite from 2002 to 2022. Initially, he examined the extent to which the seven colours varied from region to region within a given year to determine their natural fluctuations. He then expanded the analysis to observe how these annual variations in ocean colour changed over the course of two decades. This analysis revealed a clear trend that surpassed the typical year-to-year variability.

**

The above article has been published from a wire source with minimal modifications to the headline and text.