When most people hear about or contemplate global warming they think mostly of more frequent and severe storms in all seasons, larger spreads and crazy bounces in air temperature, flooding and drought, polar ice melting and so on. When the subject turns to the warming of our oceans and the calamitous results that are occurring, most people just glaze over and figure, "What the hell, they are big enough to look after themselves. Besides, it's not directly affecting my life so why should I care? I've read and heard enough bad stuff about climate change."
We have to understand there is enormous damage being done that directly affects both the environment and our very health. Damage we seldom think about but really should because we rely on the bounty from healthy oceans so much. As the health of our oceans declines, so too does our general state of health.
Kim Cobb, a marine scientist at the Georgia Institute of Technology, expected the coral to be damaged when she plunged into the deep blue waters off Kiritimati Island, a remote atoll near the centre of the Pacific Ocean. Still, she was stunned by what she saw as she descended some 10 metres to the rim of a coral outcropping. "The entire reef is covered with a red-brown fuzz," Dr. Cobb said after her recent dive. "It is otherworldly. It is algae that has grown over dead coral. It was devastating."1
The damage off Kiritimati is part of a global mass bleaching of coral reefs, the third on record and possibly the very worst. Scientists believe that heat stress from multiple weather events including the latest El Niño, compounded by climate change, has threatened more than a third of Earth's coral reefs. Many may not recover.
Coral reefs are the crucial natural incubators of the ocean's ecosystem, providing food and shelter to a quarter of all marine species, and they support fish stocks that feed more than a billion people. An estimated 30 million small-scale fishermen and women depend on reefs for their very existence. More than one million make their livelihoods from reefs in the Philippines alone.
"This is a huge, looming planetary crisis and we are sticking our heads in the sand about it," says Justin Marshall of CoralWatch at Australia's University of Queensland.2
Bleaching occurs when high heat and bright sunshine cause the metabolism of the algae - which give coral reefs their brilliant colours and energy - to speed out of control, and they start creating toxins. If temperatures drop, the corals can recover, but denuded ones remain vulnerable to disease. When heat stress continues, they starve to death. Damaged or dying reefs have been found from Réunion off the coast of Madagascar, to East Flores, Indonesia, and from Guam and Hawaii in the Pacific to the Florida Keys in the Atlantic.
The largest bleaching, at Australia's Great Barrier Reef, was confirmed last month. In a survey of 520 individual reefs that comprise the Great Barrier Reef's northern region, scientists from Australia's National Coral Bleaching Task Force found only four with no signs of bleaching. Nearly a thousand kilometres of reef had suffered significant bleaching. In follow-up surveys, scientists diving on the reef claim half the coral they had seen was dead.
Terry Hughes of the Center of Excellence for Coral Reef Studies at James Cook University in Queensland warned that even more would succumb if the water did not cool soon. "There is a good chance a large portion of the damaged coral will die," he added.3
Scientists say the global bleaching is the result of an unusual confluence of events, each of which raised water temperatures already elevate by climate change. In the North Atlantic, a strong high-pressure cell blocked the normal southward flow of polar air in 2013, kicking off the first of three warmer-than-normal winters in a row as far south as the Caribbean. A large underwater heat wave formed in the northeastern Pacific in 2014, and has since stretched along the west coast of North America, from Baja California to the Bering Sea. Nicknamed the Blob, it is two degrees Celsius warmer than surrounding waters and has been blamed for a host of add phenomena including the beaching of hungry sea lions in California and the sighting of Tropical skipjack tuna off Alaska. It can also be blamed for the disruption of the ocean's natural ability to moderate temperatures along its coastlines. As the waters warm, they can't penetrate the salt water as effectively and therefore currents don't reach the coldest regions of the deep resulting in poor cooling conditions from the displaced currents. Ambient temperatures continue to climb.
Then came 2015, with the most powerful El Niño climate cycle in a century. It blasted heat across the tropical and southern Pacific bleaching reefs from Kiritimati to Indonesia, and across the Indian Ocean to Réunion and Tanzania on Africa's east coast.
"We are currently experiencing the longest coral bleaching event ever observed," remarked C. Mark Eakin, The Coral Reef Watch coordinator at the National Oceanic and Atmospheric Administration in Maryland. "We are going to lose a lot of coral reefs during this event."4
Reefs that can take centuries to form can be destroyed in weeks. Predicting the duration of the bleaching or forecasting the next one can be difficult. The Blob has cooled somewhat, and El Niño, while weakening, is expected to stretch into 2017. Dr. Eakin said he expected the bleaching to continue for nine more months. What is clear is that these events are happening with increasing frequency - and ferocity. The previous bleachings, in 2010 and 1998, do not appear to have been as extensive or prolonged as the current one. The 1998 event killed around 16 percent of the world's coral. By 2010, oceans had warmed enough that it took only a moderate El Niño to start another round.
Then in 2013, Dr. Eakin said, "a lot of bleaching happened due to climate change, before the El Niño had even kicked in." Reefs bleached in 2014, like those in the Florida Keys and the Caribbean, had no time to begin regenerating before suffering further thermal stress from El Niño last year.
El Niño warms the equatorial waters around Kiritimati Island more than anywhere else in the world, making it a likely harbinger for the health of reefs worldwide. That is why Dr. Cobb, the Georgia Tech scientist who made the recent dive, has been making the trek at least once a year for the past 18 to the tiny ring of coral.
Though the atoll sits just north of the Equator, trade winds suck water up from the depths usually keeping the water temperature surrounding the reefs a healthy, nearly constant 25 degrees Celsius. But in 2015, the expected upwelling of deep cold water did not happen, Dr. Cobb said. So water in the atoll was 6.5 degrees warmer than normal and never cooled enough to allow coral to recover.
"The worst has happened," she warned. "This shows how climate change and temperature stresses are affecting these reefs over the long haul. This reef may not ever be the same."5
If we continue on this path of destruction and/or depletion of our natural resources i.e. coral reefs, and ignore this canary on the coalmine' we run the risk of the earth reaching its best by' date before its time.
1 Michelle Innis. "Warmer Oceans Are Killing Reefs" The New York Times International Weekly. (April 16, 2016):
2 Ibid
3 Ibid
4 Ibid
5 Ibid
