Climate Change Is Biggest Threat to Coral Reefs, Oceans: Scientists

Coral reefs are the spawning ground and nurseries for a quarter of all the ocean’s half million species

As San Franciscans get behind a ban on plastic straws, climate scientists are calling on national governments to step up against a much larger threat to our oceans.

NBC Bay Area's Mark Matthews recently traveled to Papua New Guinea to dive with the directors of a coral research station who warn that local efforts to protect our oceans aren’t going to save them.

Papua New Guinea is a world class diving destination, but like every other part of the ocean, it’s changing. Charlie Makray of Australia has been diving Papua for 30 years, and he says the numbers of big fish have depleted.

"There were areas that when you hit the water for the first time, you were surrounded by massive amounts of fish -- sharks, large fish -- and predominately you don’t see that nowadays, especially the large species and especially the sharks," Makray said. "There are some places where you just don’t see sharks at all."

Around the globe, commercial fishing has depleted the numbers of big fish, and climate change is threatening the coral reefs, the most diverse ecosystem on Earth.

Lyle Vail and Anne Hoggett, co-directors of the Lizard Island Research Station that is used by both Stanford and UC Berkeley, have been there for 28 years. In the past few years, they have seen massive devastation.

"The last four to five years have really seen some drastic changes due to elevated sea temperatures," Vail said.

Hoggett talked about coral bleaching, saying 95 percent of the reef around the station was hit in 2016. Water temperatures need only rise a few degrees above normal, and coral will expel the algae living in their tissues turning completely white.

"It’s like nothing anybody has seen before," Hoggett added. "It’s unbelievable."

In April, scientists with the National Oceanic and Atmospheric Administration reported half the coral on the Great Barrier Reef has bleached and died in the past two years.

"It’s very important to not throw your plastic straws into the water or use them even initially," Vail said. "But the big thing for coral reefs is elevated sea temperature.

"We know what we need to do; it’s not rocket science," he added. "We just need to have the political will to do it."

That is stop putting carbon into the atmosphere. Scientists say that must be done on a global scale if it’s going to have an impact. Coral reefs are the spawning ground and nurseries for a quarter of all the ocean’s half million species. Temperature change, ocean acidification, hurricanes and cyclones are all having a devastating impact. All are issues scientists have linked to climate change.

"It’s got to stop. We’re on the road to ruin," Hoggett said. "People say coral reefs are the canary in the coal mine. It’s really quite trite, but it’s so true. They are singing loud and clear."

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