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Global warming may directly impact ocean phytoplankton: even if all Paris Agreement goals are met, the sea color will change by 50% by 2100

Global warming may cause another change on the Earth’s features: the blue planet may become bluer due to a rise in global temperature in the next decades. That’s what a study recently published in the scientific journal Nature Communications says.

According to the study, led by scientist Stephanie Dutkiewicz, at the Massachusetts Institute of Technology (MIT), one of the outcomes of global warming is the increase of phytoplankton, a group of microscopic marine organisms that absorb and reflect light.

“(…) phytoplankton turns sunlight into chemical energy, and consumes carbon dioxide. That’s the bottom rung on the marine food chain.” – Stephanie Dutkiewicz, at the Massachusetts Institute of Technology (MIT)

“We see that the color will change. However, this change probably won’t be visible to the naked eye, but of course the sensors will be able to reveal that there are changes,” says Dutkiewicz in an interview with British broadcaster BBC. “And it will likely be one of the earliest warning signals that we have changed the ecology of the ocean”, he completes.

How global warming changes the Earth’s color

The rise in global temperature has a direct impact on seawater circulation, and this shifts the amount and quality of food available for these minuscule organisms. This may result in phytoplankton decrease, whose presence gives greenish shades to the water. Without them, the ocean will turn bluer.

North Atlantic is expected to be among the first ones to see such change, followed by the Antarctic Ocean region.

The team of researchers designed a simulation that estimates effects of the average rise in the planet’s temperature of 3°C by 2100 – a scenario close to that expected if the Paris Agreement goals are met. In this setting, by the end of the century, there will be over 50% of color change in the world’s oceans.

“The color in the blue-green range is going to show that signal of change sooner. In some places, maybe in the next decade,” said Dutkiewicz. And the outcome for global biodiversity may be a disaster: phytoplankton turns sunlight into chemical energy, and consumes carbon dioxide, which is the bottom rung on the marine food chain.

“It could be potentially quite serious. If climate change shifts one community of phytoplankton to another, that will also change the types of food webs they can support.” warns the scientist.

Content published in March 22, 2019

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