Melting glaciers and bleached corals: We hear about them a lot when it comes to the effects of global warming on our oceans.
But other impacts are not so visible—like whole species of fish, seabirds and turtles moving to live in cooler waters closer to the poles.
These changes are highlighted in a new report released this week by the International Union for Conservation of Nature that calls ocean warming “the greatest hidden challenge of our generation”.
The report, authored by 80 contributing scientists from a dozen countries, was released during an international conservation summit in Honolulu, PRI reported.
The findings were stark: The ocean acts as a shield against global warming, absorbing much of the heat and carbon dioxide emitted by humans. Since the 1970s, more than 90% of Earth’s greenhouse-related heating has been absorbed by the oceans, according to the report.
If it were not for the oceans, the authors of the report say Earth’s atmosphere would have warmed nearly 100 degrees since 1955.
Co-author Samantha Chapman, an ecologist at Villanova University in Pennsylvania, explains that water molecules can absorb a lot of heat and the oceans are huge.
“They’re just so massive; two-thirds of our planet are made up of the ocean,” Chapman says.
All this extra heat in the world’s oceans is leading to its deoxygenation and a slowdown of ocean circulation.
It’s changing where seaweed grows, how turtles eat and when fish spawn.
Species are moving toward the poles to find cooler waters, throwing food webs out of whack.
Chapman gives an example: “When plankton move to different places and for example the animals that eat them aren’t cued by the same cues but rather by navigating by the stars or by the amount of daylight, then they don’t move at the same rate, and therefore the things they eat are no longer there.”
The report’s recommendations include recognizing the severity of ocean warming impacts on ocean ecosystems and the benefits they provide to humans, expanding marine protected areas, introducing legal protection for the high seas, better evaluating the socioeconomic risks associated with warming oceans and continuing to fill gaps in scientific knowledge, as well as cutting greenhouse gas emissions rapidly and substantially.
