Category Archives: Coral bleaching

The new normal (part 22): The Great Barrier Reef is dying

Source: The Age

A little over two years ago I took my first trip to north Queensland with the express purpose of seeing the Great Barrier Reef (GBR) and the magnificent rain forests of the region. I was motivated by the thought it may be one of those “last chances to see” the GBR before its inevitable decline.

While there I could no help but feel a muted, but still profound, sense of melancholy.

I could not help but recall my child hood experience of watching David Attenborough’s Life on Earth. What I saw was beautiful, complex and fascinating and yet fragile and at risk.

For some time scientists have understood the Great Barrier Reef is at risk – today a report in The Age today confirms that over the past 30 years half of the GBR’s coral has disappeared due to parasites, cyclone damage and coral bleaching:

Half the Great Barrier Reef’s coral has disappeared in the past 27 years and less than a quarter could be left within a decade unless action is taken, a landmark study has found. 

A long-term investigation of the reef by scientists at Townsville’s Australian Institute of Marine Science found coral had been wiped out by intense tropical cyclones, a native species of starfish and coral bleaching. 

Researchers warned that while the World Heritage listed reef was a dynamic system — with coral cover rising and falling over time — if the mass die-off continued less than 25 per cent would exist in 2022. 

“The big concern going forward is that if nothing else changes than within 20 years the reef could be in a perilous state,” said institute senior scientist Peter Doherty. 

At 214 reef sites surveyed, the coral cover halved from 28 to 13.8 per cent between 1985 and 2012.

Two-thirds of the loss occurred since 1998. Only three of the 214 reef sites exhibited no impact. 

“Coral cover is the simplest index of reef health, and the health of the Great Barrier Reef has gone down dramatically,” said institute senior scientist Hugh Sweatman. 

“The coral provides shelter and food for thousands of organisms so you don’t just lose the corals themselves you lose the species that depend on them.” 

The coral damage was most pronounced in the central and southern regions of the 2000-kilometre reef, with the remote northern section remaining largely unaffected.

Tropical cyclones accounted for 48 per cent of the coral die-off across the entire reef, followed by outbreaks of the crown of thorns starfish, which was responsible for 42 per cent of the loss. Bleaching contributed to 10 per cent of loss. 

“You can dive on a coral reef one week when all you can see is living coral, each colony overlapping with its neighbours, but after the passage of a cyclone it looks like a cement road,” said Dr Doherty. 

Global warming models project increases in water temperatures will lead to more intense cyclones.

While crown of thorns starfish were a natural predator of coral — the adult animals feed on tiny polyps inside the coral skeleton — their impact over the past 25 years had been substantial. 

A large outbreak that started around Lizard Island in 1994, spread the length of the reef over 15 years.

Flood waters carrying fertilisers and other agricultural nutrients into the ocean were thought to increase the survival of crown of thorns larvae because the runoff encouraged the growth of algae eaten by the offspring.


“The frequency of crown of thorns outbreaks on the Great Barrier Reef has likely increased from one in every 50-80 years before European agricultural runoff, to the currently observed frequency of one in about every 15 years,” said the authors. 

Warmer waters were also responsible for coral-bleaching events, where the tiny organisms living inside the coral skeleton “bleached” and died with the rising temperatures. 

“The recent frequency and intensity of mass coral bleaching are of major concern, and are directly attributable to rising atmospheric greenhouse gases,” wrote the authors, whose study is published in the journal Proceedings of the National Academy of Sciences.

“Bleaching mortality will almost certainly increase in the GBR, given the upward trend in temperatures,” they said. 

While the state of the world’s longest reef system appeared bleak, it did have the ability to recover.

“What it needs is a decade or two to do it in,” said Dr Sweatman.

This too shall pass.

The maths: the must read article by McKibben, the implications we must consider

Bill McKibben’s powerful Rolling Stone article is currently being pinged around Twitter.

It is essential reading: powerful, insightful, reasoned and passionate.

I implore you to read it and pass it around:

When we think about global warming at all, the arguments tend to be ideological, theological and economic. But to grasp the seriousness of our predicament, you just need to do a little math. For the past year, an easy and powerful bit of arithmetical analysis first published by financial analysts in the U.K. has been making the rounds of environmental conferences and journals, but it hasn’t yet broken through to the larger public. This analysis upends most of the conventional political thinking about climate change. And it allows us to understand our precarious – our almost-but-not-quite-finally hopeless – position with three simple numbers.

McKibben highlights what he calls the “three most important” numbers you did to know.

Firstly, the so called “2 degree safe limit”:

The accord did contain one important number, however. In Paragraph 1, it formally recognized “the scientific view that the increase in global temperature should be below two degrees Celsius.” And in the very next paragraph, it declared that “we agree that deep cuts in global emissions are required… so as to hold the increase in global temperature below two degrees Celsius.” By insisting on two degrees – about 3.6 degrees Fahrenheit – the accord ratified positions taken earlier in 2009 by the G8, and the so-called Major Economies Forum. It was as conventional as conventional wisdom gets.

To maintain global temperatures under the “safe level” we need to restrict the amount of carbon we pump into the atmosphere – no more than 575 gigatons:

Scientists estimate that humans can pour roughly 565 more gigatons of carbon dioxide into the atmosphere by midcentury and still have some reasonable hope of staying below two degrees. (“Reasonable,” in this case, means four chances in five, or somewhat worse odds than playing Russian roulette with a six-shooter.)

However, there are close to 3000 gigatons worth carbon locked up in the available reserves of fossil fuels:

This number is the scariest of all – one that, for the first time, meshes the political and scientific dimensions of our dilemma. It was highlighted last summer by the Carbon Tracker Initiative, a team of London financial analysts and environmentalists who published a report in an effort to educate investors about the possible risks that climate change poses to their stock portfolios. The number describes the amount of carbon already contained in the proven coal and oil and gas reserves of the fossil-fuel companies, and the countries (think Venezuela or Kuwait) that act like fossil-fuel companies. In short, it’s the fossil fuel we’re currently planning to burn. And the key point is that this new number – 2,795 – is higher than 565. Five times higher.

And that the economic imperatives and self interest of fossil fuel companies will drive us beyond the 575 gt:

If you told Exxon or Lukoil that, in order to avoid wrecking the climate, they couldn’t pump out their reserves, the value of their companies would plummet. John Fullerton, a former managing director at JP Morgan who now runs the Capital Institute, calculates that at today’s market value, those 2,795 gigatons of carbon emissions are worth about $27 trillion. Which is to say, if you paid attention to the scientists and kept 80 percent of it underground, you’d be writing off $20 trillion in assets. The numbers aren’t exact, of course, but that carbon bubble makes the housing bubble look small by comparison. It won’t necessarily burst – we might well burn all that carbon, in which case investors will do fine. But if we do, the planet will crater. You can have a healthy fossil-fuel balance sheet, or a relatively healthy planet – but now that we know the numbers, it looks like you can’t have both. Do the math: 2,795 is five times 565. That’s how the story ends.

As I tried to say, with far less eloquence than McKibben we are locking in the March of folly. There is much to say and debate about how to respond to the issues outlined in the article.

2010 climate death toll hits 21,000 while coral reefs around the globe die

Nothing unusual at all...

Oxfam reports:

“A new Oxfam report “More than ever: climate talks that work for those that need them most”, says that 21,000 people died due to weather-related disasters in the first nine months of 2010 – more than twice the number for the whole of 2009. This year is on course to experience more extreme-weather events than the ten-year average of 770. It is one of the hottest years ever recorded with Pakistan logging 53.7°C – the highest ever in Asia.

Report author Tim Gore of Oxfam said: “This year has seen massive suffering and loss due to extreme weather disasters. This is likely to get worse as climate change tightens its grip. The human impacts of climate change in 2010 send a powerful reminder why progress in Cancun is more urgent than ever.”

While Hot Topic reports on the massive episodes of coral bleaching around the globe:

“The Telegraph article noted scientists in Thailand have reported reefs suffering 90% of their corals being bleached and up to 20% of the corals dead. Olivia Durkin, who is leading the bleaching monitoring at the Centre for Biodiversity in Peninsular Thailand, said: “This year’s severe coral bleaching has the potential to be the worst on record.”

In June The Maldives reported the most serious incidence of coral bleaching since the major 1998 El Niño-event that destroyed most of the country’s shallow reef coral. Since then there has been gradual reef recovery but the 2010 event will be at least a major setback…”

A 100km square kilometre iceblock breaks of Greenland.

A super storm, the likes rarely seen before hits the middle of the US (see image above).

The Amazon is experiencing a severe drought.

Record snow storms across Europe and the US, severe flooding in Poland (killing 12 people).

But of course, it’s all just a co-incidence. 

%d bloggers like this: