Ocean color change is likely due to climate change.

Ocean color change is likely due to climate change.

The Changing Color of the Oceans: A Reflection of Climate Change


Think about the breathtaking beauty of the oceans. The deep sapphire blues and crystal-clear waters have fascinated us for centuries. But what if we told you that these colors are changing? Yes, you heard it right! Over the past two decades, the color of our oceans has been transforming, and it’s causing concern among scientists. This change in color is not just an optical illusion; it is a tangible reflection of the impact of climate change on our planet.

“I’ve been running simulations that have been telling me for years that these changes in ocean color are going to happen,” says Stephanie Dutkiewicz, a senior research scientist in Massachusetts Institute of Technology’s Department of Earth, Atmospheric and Planetary Sciences. “To actually see it happening for real is not surprising, but frightening. And these changes are consistent with man-induced changes to our climate,” Dutkiewicz adds.

While imperceptible to the human eye, the color changes have occurred in over 56% of the world’s oceans, covering an area larger than the total land area on Earth. These transformations are most noticeable in tropical ocean regions near the equator, where the waters have become progressively greener. Such changes imply that the ecosystems within the surface ocean must also be undergoing significant alterations.

“This gives additional evidence of how human activities are affecting life on Earth over a huge spatial extent,” explains B.B. Cael of the National Oceanography Centre in Southampton, England, who led the study.

But why are these color changes a cause for concern? Well, deep blue water, which reflects very little life, is being replaced by greener waters that indicate the presence of ecosystems, including phytoplankton. Phytoplankton are microscopic plant-like organisms containing chlorophyll, the green pigment that helps them capture carbon dioxide and sunlight, vital for their survival. More than just serving as the foundation of the marine food web, phytoplankton play a crucial role in the ocean’s ability to capture and store carbon dioxide.

To investigate these color changes, researchers analyzed ocean color measurements taken by the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Aqua satellite, which captures images in seven visible wavelengths. B.B. Cael conducted a statistical analysis using all seven colors measured by MODIS from 2002 to 2022, examining how much the colors changed from region to region annually and how these variations evolved over two decades. Astonishingly, the results of Cael’s analysis aligned closely with Dutkiewicz’s 2019 model, which simulated the Earth’s oceans with and without greenhouse gases. This parallel suggests that the observed color trends are not random variations but rather an outcome of human-led climate change.

“The color of the oceans has changed,” Dutkiewicz states. “And we can’t say how. But we can say that changes in color reflect changes in plankton communities, which will impact everything that feeds on plankton. It will also change how much the ocean will take up carbon because different types of plankton have different abilities to do that. So, we hope people take this seriously. It’s not only models that are predicting these changes will happen. We can now see it happening, and the ocean is changing.”

This research, partially funded by NASA, sheds light on an alarming consequence of climate change. The study’s findings were published on July 12 in the journal Nature, affirming the urgent need to address these environmental transformations.

Key Points:

  • The color of the oceans is changing due to climate change.
  • Over 56% of the world’s oceans have undergone color transformations, primarily in tropical regions near the equator.
  • The changes reflect alterations in plankton communities, which are essential for the ocean’s health and carbon capture.
  • Researchers used satellite data from NASA’s Aqua satellite to analyze the ocean’s color changes.
  • The findings from real-world data closely matched earlier models, providing further evidence of human-led climate change.
  • This research highlights the crucial importance of taking immediate action to address climate change and preserve our oceans’ delicate ecosystems.

QUESTION: What percentage of the human body is water?

Answer: The human body is approximately 60% water.

For more information, visit NASA to learn more about climate change.

SOURCE: Massachusetts Institute of Technology, news release, July 12, 2023