Extreme Temperature Diary- Sunday October 18th, 2020/ Main Topic: New Evidence That Climate Change Has Killed Half of the Great Barrier Reef’s Corals

The main purpose of this ongoing blog will be to track United States extreme or record temperatures related to climate change. Any reports I see of ETs will be listed below the main topic of the day. I’ll refer to extreme or record temperatures as ETs (not extraterrestrials).😉

Main Topic: New Evidence That Climate Change Has Killed Half of the Great Barrier Reef’s Corals

Dear Diary. One big item from last week that deserves to be our main topic of the day is news about Australia’s Great Barrier Reef. This century the expansive underseas coral forest has become climate crisis’s canary in the coal mine, and this bird is now signing in alarm. Apparently scientists have found that the reef is being killed off much faster than originally thought.

Here are details from the Smithsonian Magazine:

Climate Change Has Killed Half of the Great Barrier Reef’s Corals

A new study finds corals on the Australian mega-reef declined 50 percent between 1995 and 2017

Great Barrier Reef
Fish and corals on Australia’s Great Barrier Reef. Between a quarter and a third of all marine species spend some part of their life cycle in coral reefs. (Andreas Dietzel)

OCTOBER 15, 2020

Australia’s Great Barrier Reef, the largest coral reef ecosystem in the world, lost half of its corals between 1995 and 2017, report Myles Houlbrook-Walk and Ollie Wykham for the Australian Broadcasting Corporation (ABC News). The new study, published this week in the journal Proceedings of the Royal Society B, found that nearly every coral species and size found on the Great Barrier Reef had declined, reports Maria Cramer for the New York Times.

Covering nearly 133,000 square miles and hosting more than 1,500 species of fish, 4,000 types of mollusk and 400 species of coral, the Great Barrier Reef is a vital marine habitat and a priceless crown jewel of the world’s ocean ecosystems.

For the new study, researchers with the Australian Research Council’s Center of Excellence for Coral Reef Studies measured changes in coral colony sizes along the Great Barrier Reef’s more than 1,400-mile length between 1995 and 2017.

“We found the number of small, medium and large corals on the Great Barrier Reef has declined by more than 50 percent since the 1990s,” Terry Hughes, a coral researcher at James Cook University and senior author of the study, says in a statement. “The decline occurred in both shallow and deeper water, and across virtually all species—but especially in branching and table-shaped corals.”

Losses among large corals are especially concerning, because reefs rely on these big, mature corals to produce vast numbers of offspring that help perpetuate or revive surrounding reefs. The researchers say their results suggest the Great Barrier Reef’s resilience, or ability to recover from damage, has been severely compromised since the 1990s.

“We used to think the Great Barrier Reef is protected by its sheer size—but our results show that even the world’s largest and relatively well-protected reef system is increasingly compromised and in decline,” says Hughes in the statement.

The staggering loss of corals was driven largely by marine heatwaves in 2016 and 2017—and to a lesser extent, 1998 and 2002—that resulted in massive coral die-offs, per ABC News. Elevated water temperatures stress the corals, and this strain can cause the photosynthetic algae corals rely on for much of their sustenance to either die or eject from their former symbionts. This has the effect of turning the corals bone-white, which is the genesis of the phenomenon’s name: coral bleaching. Without the algae, called zooxanthellae, the corals typically starve to death or succumb to disease.

Human-caused climate change is the primary driver of the rising ocean temperatures that have killed off half of the reef, Andreas Dietzel, a coral researcher at James Cook University and first author of the new research, tells ABC News. “We can clearly correlate the rising temperatures to coral mortality and bleaching on the Great Barrier Reef,” he says.

Earth’s rising average temperatures are expected to continue the reef’s decline, Terry Hughes, a coral researcher at James Cook University and senior author of the study, tells Darryl Fears of the Washington Post. “The only effective way to improve the outcome for coral reefs is global action on greenhouse gasses. If global temperatures rise to 3 or 4 [degrees Celsius], the reef will be unrecognizable, so there is no time to lose.”

Alex Fox

Alex Fox is a freelance science journalist based in Washington, D.C. He has written for ScienceNatureScience Newsthe San Jose Mercury News, and Mongabay. You can find him at Alexfoxscience.com. Read more from this author | Follow @Alex_M_Fox

I’ve been reporting on the Great Barrier Reef ever since starting thus site in 2017. Every time I do so there is no good news, so I’m just shaking my head. I hate to beg and plead, but please help our environment by cutting down on the use of fossil fuels. Thanks so much if you do.

Here is more climate and weather news from Sunday:

(As usual, this will be a fluid post in which more information gets added during the day as it crosses my radar, crediting all who have put it on-line. Items will be archived on this site for posterity. In most instances click on the pictures of each tweet to see each article. The most noteworthy items will be listed first.)

Now here are some of today’s articles and notes on the horrid COVID-19 pandemic:

(If you like these posts and my work please contribute via the PayPal widget, which has recently been added to this site. Thanks in advance for any support.) 

Guy Walton “The Climate Guy”

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