El Niño storms seem to be strengthening due to climate change, and in turn intensifying coral bleaching. This is particularly vivid at Christmas Island, where the water has warmed the most, writes Robynne Boyd for the Pacific Standard.

Climate scientist Kim Cobb first noticed the whitish hue of the corals around Kiritimati, a large atoll located south of Hawai‘i, while on a research trip in July of 2015.

Though 18 years had passed without any bleaching, a strong El Niño was now blowing its warm breath across the Pacific, draining colour from the reef’s spiky, tubular, and bulbous corals, leaving them pallid and skeletal.

Last year was one of unusual climatic activity, with El Niño causing extreme weather around the world. The year 2015 was also dubbed the hottest on record, according to the National Oceanic and Atmospheric Administration and the National Aeronautics and Space Administration.

“My research site is in the very middle of the Pacific Ocean,” says Cobb, a Georgia Institute of Technology climate scientist who studies the effects of specific El Niño and La Niña climate patterns on coral reefs.

“And this El Niño event has laid the maximum ocean warming smack in the middle of my research site.”

If the globe were an archery target with the warmest ocean temperatures in the centre and the coolest on the outer edge, Kiritimati, or Christmas Island as it’s sometimes called, would be the bullseye.

It is the broiling centre of a problem affecting reefs globally – a strong El Niño, exacerbated by climate change, is killing off the world’s coral.

Christmas Island could also provide a glimpse at what the reefs of the future might look like, should ocean temperatures continue to rise.

Upon diving into Christmas Island’s crystalline waters last November, Cobb and her research team found that 50 to 90 per cent of the corals had undergone some level of bleaching. As many as 30 per cent were already dead.

“It was absolutely jaw dropping,” says Cobb, who has been visiting Christmas Island since the last intense El Niño, in 1997.

“From having personally never witnessed any bleaching on this reef, to seeing whole traps of the reef being completely dead, to whole species wiped out. It was far worse than I expected.”

As with many an El Niño before it, the Pacific Ocean began heating up in the summer of 2015, reaching its peak before the year’s end.

During an El Niño, the strong trade winds that usually blow from east to west across the Pacific weaken and waft in the opposite direction. The ocean pushes against the diminished winds, which kicks off a subsurface wave that moves eastward, bringing the warm surface waters with it.

As the eastern Pacific heats up, the trade winds weaken further. This feedback loop continues until the winds collapse, and El Niño cycles vanish with the arrival of spring.

It’s important to remember that El Niño is a pervasive and natural component of the climate system. It is one stage within a large climate pattern known as the El Niño-Southern Oscillation, or ENSO, that increases and decreases the temperatures in the Pacific Ocean in somewhat predictable cycles, thereby affecting climate worldwide.

There have only been two “super” El Niños until now. The first occurred in 1982–83, and the second in 1997–98. The El Niño we’re currently experiencing has exceeded both in terms of temperature.

The current El Niño set a record in November for the warmest waters documented in the equatorial Pacific over a one-week period, according to Weather Underground.

For one week in November, temperatures rose 5.4 degrees Fahrenheit above the region’s average. The previous record of 5.04 degrees Fahrenheit above average took place in November of 1997.

At the height of warming, Christmas Island’s surrounding waters were 88 degrees Fahrenheit (31.1C), seven degrees higher than average.

The million-dollar question, then, is whether El Niños are intensifying due to climate change, and in turn aggravating coral bleaching? To that, Cobb has a grim answer: “Our work is showing yes.”

Cobb says the answer is in the data, and the data demonstrates that El Niños have been strengthening in the recent past.

In 2013, after examining fossilized coral cores – long tubes of coral skeleton drilled out of reefs or large pieces of coral – Cobb published a paper showing that El Niños were more intense and variable in the 20th century than over the last 7000 years.

Cobb’s research is one data point in a growing list that make the connection between strengthening El Niño events and global warming. She says a number of recent studies all point to mounting carbon dioxide levels as a key component.

Also in 2013, for example, Shang-Ping Xie, a climate researcher at the University of California–San Diego’s Scripps Institution of Oceanography, analysed tree ring patterns from the tropics and mid-latitudes.

His results, published in Nature Climate Change, depicted unusually high El Niño-Southern Oscillation activity toward the end of the 1900s.

One year later, another study led by Wenjun Cai, a climate modeler at Australia’s Commonwealth Scientific and Industrial Research Organisation, found that climate change could double the frequency of super El Niño events.

It’s not exactly clear how this will play out for coral reefs. But Xie foresees three major changes. First, oceans around the world will continue to warm. This uptick in temperature leads to increased warming in the equatorial Pacific, which in turn intensifies El Niños. All of this is hard on coral life, which need sustained, warm (but not hot) temperatures to remain unbleached and healthy.

At the start of October 2015, the NOAA confirmed that the third global coral bleaching event – the first occurred during a strong El Niño in 1998; a second came in 2010 – was cooking the oceans.

The bleaching began in the North Pacific in 2014, and has spread around the world. The areas hit hardest include the Hawaiian Islands, the Caribbean, and parts of the southeast Pacific and Indian Ocean.

Coral reefs provide nursery grounds, food, and shelter for over 25 per cent of all marine life. With an estimated quarter of reefs already damaged, any additional threats, such as climate change, impede the benefits they deliver humanity—coastal protection, tourism, fishing revenue, and splendour.

When stressed, whether from changes in temperature, light, or nutrients, corals release their symbiotic algae that live in their tissue.

The loss of algae turns corals white and makes them more susceptible to disease. Severe bleaching can devastate reef systems, weakening their overall capacity to recover.

A reef hosts a huge diversity of marine life; some fish rely on coral tissue as food, and many have an aversion to degraded reefs. As reefs weaken, so does the food web they support.

“It’s the multiple interacting impacts that give the key to disaster,” says Jennifer Smith, a marine ecologist at Scripps Institution of Oceanography.

“If we turned the ocean up by four degrees tomorrow, corals wouldn’t make it. But, if that temperature increase happens over 100 years – I think reefs are pretty good at handling single stress events.”

Smith names the Palmyra Atoll reefs, which she has frequented and studied, as an example of a place that looks almost exactly the same as it did 2000 years ago. Far from any local human population, Palmyra’s reefs retain 80 to 90 per cent of corals, despite past bleaching and ocean acidification.

Even if corals are heavily bleached during super El Niños, Smith believes “we might have a different suite of corals in the future. These organisms have been around for many hundreds of thousands of years and will find a way to adapt or acclimate.”

Meanwhile, Cobb will return to Christmas Island later this month, where she’ll be joined by University of Victoria marine ecologist Julia Baum, to record the level of bleaching and coral mortality.

She’s not expecting a promising reversal: “Judging by how distressed the reefs were during our last visit,” Cobb says, “we’re expecting the maximum death and destruction.”

- Robynne Boyd began writing about people and the planet while living barefoot and by campfire on the North Shore of Kauai, Hawai‘i. Over a decade later and now fully dependent on electricity, she continues this work as a freelance environment writer based in Decatur, Georgia.

Conservation of rainforests essential

PORT MORESBY – The latest report from the University of Papua New Guinea’s Remote Sensing Centre shows pristine rainforest and unique species are being lost, and they are calling on PNG not to go ahead with major new logging concessions.

There are also concerns about the climate change impact of new logging, including for countries in South East Asia where weather is influenced by moisture from PNG’s forests.

It took scientists two-and-a-half years to piece together evidence from satellite images to produce their report, State of the Forests of Papua New Guinea 2014.

The report found 11,457 square kilometres of pristine forest had been cleared or logged between 2002 and 2014.

Australia’s Wet Tropics Heritage Area, which stretches more than 600 kilometres from Cooktown to Townsville, is less than 9000 square kilometres.

Deforestation accounted for 3752 square kilometres of PNG’s forest loss while degradation of previously unlogged forest accounted for 7705 square kilometres.

The island provinces of Manus, New Ireland, East and West New Britain saw the greatest proportion of change, followed by West Sepik and Gulf provinces.

“The biggest driver of that change was the expansion of industrial logging into previously unlogged areas,” said Jane Bryan, lead author of the report.

In older logging concessions repeat harvesting as soon as 15 years into the 35-year cutting moratorium is widespread, the report said.

Chapters by some of the world’s leading scientists highlight climate and biodiversity concerns over the PNG Government’s plan to release massive new logging concessions in the Kamula Doso-Strickland region of Western province.

Research published by Russian physicists Anasatasia Makarieva and Victor Gorshkov suggests the role of windblown moisture from PNG’s mainland forests in cooling and creating rainfall in South East Asia and beyond may have been be underestimated.

“PNG’s forests contribute to the maintenance of this current favourable climatic regime,” they said.

“Their devastation could trigger adverse changes in local, regional and possibly global climates.”

At the UN climate change negotiations in Paris, the PNG government pledged to prevent logging and clearing in millions of hectares of rainforest as part of its contribution to fighting global warming.

“Forests are large stores of carbon and right now most of the world’s temperate forests have been cleared,” said climate expert and Australian National University Emeritus Professor Will Steffen, another contributor.

“The big remaining stands of forest in the tropical regions of the world are very important for maintaining carbon in the landscape – not in the atmosphere.”

Papua New Guinea is the meeting point for species from South East Asia and Australasia, creating a rich biodiversity which includes many rare and unique plants and animals.

Researchers are only beginning to catalogue its resources, becoming one of the few places where scientists are still finding mammals, reptiles and amphibians new to science.

State of the Forests contributor and head of the University of Papua New Guinea’s biological sciences division, Associate Professor Osia Gideon, says logging means species are at risk of being wiped out before the world knows of their existence.

“It is a very high risk that PNG will lose species before they become known to science,” he said.

Associate Professor Gideon says the PNG government’s lack of action is disturbing.

“PNG is a signatory to a number of international conventions about biodiversity conservation but in terms of efforts on the ground it has been extremely disappointing,” he said.

“For the benefit of the nation and the future generations we need to be able to set aside conservation areas, we need to be able to preserve the wealth of this country so that future generations could enjoy what we are currently enjoying.”

- ABC