You might have grown up thinking of the ocean as the “big blue,” but it’s time for a reality check. Over the past two decades, more than half of the world’s oceans have experienced a serious makeover – they’re turning green. Yeah, you heard it right, green! And what’s the culprit behind this transformation? You guessed it, climate change.
Recent research published in Nature has dropped a bombshell: 56% of our oceans have undergone a visible color shift from 2002 to 2022. Isn’t it mind-boggling that we’re talking about more than half the world’s oceans changing color?
The ocean, like a chameleon, can change its color due to several reasons, such as light reflection off particles and sediments, decaying organic matter, and so forth. But the headlining act in this color play is the humble phytoplankton. These minuscule plant-like microbes, the unsung heroes of the marine food chain, capture and store carbon dioxide. Similar to their terrestrial cousins, they contain chlorophyll, which contributes to color variation in the ocean.
While our eyes see the ocean as primarily blue, the reality is a kaleidoscope of wavelengths including blue, green, and even red. Thanks to the Moderate Resolution Imaging Spectroradiometer (aka MODIS) aboard NASA’s Aqua satellite, researchers have access to sensors that can perceive color differences that our eyes can’t. It’s like having a superpower to see the changing colors of our world’s oceans.
What’s even more interesting is that certain regions of the ocean are getting a heavier green makeover than others. Researchers noted that tropical oceanic areas near the equator are turning greener at a faster pace compared to other parts of the globe.
Here’s where things get serious. It’s clear that the natural ebb and flow of phytoplankton blooms, whether seasonal or annual, don’t account for the drastic color shift we’re witnessing. The green invasion in our oceans is likely a symptom of a deeper issue: excessive carbon dioxide absorption by plankton and algae communities.
This alarming green wave carries a dire warning. Oceans, our invaluable carbon sinks, soak up nearly a quarter of the world’s carbon emissions. However, if the green color intensifies, it could indicate that our oceans are reaching their limit in absorbing more carbon. We are at risk of losing one of our most crucial defenses against climate change.
This isn’t just about the world’s oceans getting a fresh coat of green paint. This is a dire, neon green warning sign that our actions are irrevocably altering the planet. As millennials, we bear the brunt of this crisis and have the power to act. This ‘green alert’ should rally us to demand more substantial climate action. The time for change is now.