The Great Barrier Reef is perhaps on its final deathbed as it suffers from back to back massive dying events in the past two years. Australia's Great Barrier Reef is one of the great natural wonders of the world, a tremendous display of beauty, biodiversity, and a fragile ecosystem. Now, the reef faces mass destruction as a result of warming seas caused by climate change.
Last year the reef suffered a widespread bleaching event that damaged 95 percent of the reef's northern most third. This year, without hardly enough time to recover the middle third of the reef has suffered widespread bleaching, as discovered by a recent aerial survey taken by the ARC Center of Excellence for Coral Reef Studies.
During this expedition, the center found hundreds of miles of coral ecosystems dead due to sea temperatures warming above the habitable range for corals. The study, recently published in Nature, surveyed what ecologists and marine biologists have been fearing may be true, the terminal decline of the Great Barrier Reef.
Since the 1980's scientists have consistently surveyed the reef to document its vitality and changes through time. During those several decades, they have noticed increasing occurrence and severity of bleaching events caused largely by warming ocean temperatures and pollutants from agriculture and industrialization.
The Great Barrier reef is a victim of global climate change and its decline is a direct result of a warming planet. This recent aerial survey covered over 5,000 miles of reef and documented over 800 individual coral reefs. Of the aforementioned 5,000 miles of reef the surveyors found 932 miles have been bleached, close to 20 percent. To make things worse, this came just a year after approximately 93 percent of the reef suffered damage due to warming. As if that wasn't enough damage, the reef was recently struck by the Tropical Cyclone Debbie, turning reef into rubble along an area that had previously escaped from bleaching.
— Terry Hughes (@ProfTerryHughes) April 10, 2017
The bleaching of the Great Barrier Reef is primarily caused by climate change driven global warming and secondly so from pollution and runoff from land. When sea temperatures get too warm the symbiotic relationship between corals and zooxanthellae become strained. Zooxanthellae are algae that live within corals and provide nutrients and produce oxygen for the coral.
Alternatively, the coral provides a safe environment and nutrients for photosynthesis. When temperatures get too warm the algae produce toxins that force the coral to eject the zooxanthellae, a response that leaves the corals in life support if waters don't cool.
Last year, in 2016, scientists expected large scale bleaching due to the strain El Niño, which drives abnormal warming of Australian waters. However, the lack of an El Niño this year coincident with another year of bleaching provides evidence that there is a larger driver at play.
The Great Barrier Reef has experienced bleaching events in 1998, 2002, 2016, and now in 2017 since measurement began. Unfortunately, it takes over a decade for reefs to recover, but with back to back bleaching that severely limits the chances of significant recovery.
With Donald Trump's rollback of promises in the Paris Agreement, tackling climate change appears to have taken a step backward. In addition, the Australian government, which relies heavily on coal mining and export is unwilling to make the appropriate changes required to jumpstart a long-lasting revitalization of the reef. It's not too late to seriously start combating climate change, a phenomenon that has increasingly killed the Great Barrier Reef for decades.
I don’t think the Great Barrier Reef will ever again be as great as it used to be — at least not in our lifetimes,” said C. Mark Eakin with the National Oceanic and Atmospheric Administration.