Those of you who watched the ABC’s presentation of The Great Global Warming Swindle might not have been convinced by the arguments challenging the conventional wisdom that carbon dioxide is responsible for global warming. However, it should be apparent that scientists and politicians such as Al Gore, who have been telling us that the science is unquestionable on this issue, have been stretching the truth. It seems that there are some good reasons to believe that we may have been swindled.
Closer to home, there is a swindle by scientists, politicians and most green organisations regarding the health of the Great Barrier Reef (GBR). We are told that the reef is a third of the way to ecological extinction, is being smothered by sediments, is polluted by nutrients and pesticides, and is being cooked by global warming. Some scientists and organisations give the reef only a couple of decades before it is finished.
In the light of all this dismal news comes a new study by Scientists from the Australian Institute of Marine Science (AIMS) which indicates that the corals are more tolerant to rising waters temperatures than first thought by most people.
Under conditions of extremely high water temperature, corals expel the symbiotic algae called zooxanthelae that reside within the polyp making them appear bleached white. Some coral die from this bleaching and there have recently been some major mass bleaching events in the Great Barrier Reef and around the world, particularly in 1998 and 2002. The AIMS work shows that the corals can adapt to rising water temperatures by using strains of zooxanthelae that make them tolerant to higher temperatures.
In biological circles, it is common to compare coral reefs to canaries, i.e. beautiful and delicate organisms that are easily killed. The analogy is pushed further by claiming that, just as canaries were used to detect gas in coal mines, coral reefs are the canaries of the world and their death is a first indication of our apocalyptic greenhouse future. The bleaching events of 1998 and 2002 were our warning. Heed them now or retribution will be visited upon us.
In fact a more appropriate creature with which to compare corals would be cockroaches - at least for their ability to survive. If our future brings us total self-annihilation by nuclear war, pollution or global warming, my bet is that both cockroaches and corals will survive.
Their track-record is impressive. Corals have survived 300 million years of massively varying climate both much warmer and much cooler than today, far higher CO2 levels than we see today, and enormous sea level changes. Corals saw the dinosaurs come and go, and cruised through mass extinction events that left so many other organisms as no more than a part of the fossil record.
Corals are particularly well adapted to temperature changes and in general, the warmer the better. It seems odd that coral scientists are worrying about global warming because this is one group of organisms that like it hot. Corals are most abundant in the tropics and you certainly do not find fewer corals closer to the equator. Quite the opposite, the further you get away from the heat, the worse the corals. A cooling climate is a far greater threat.
The scientific evidence about the effect of rising water temperatures on corals is very encouraging. In the GBR, growth rates of corals have been shown to be increasing over the last 100 years, at a time when water temperatures have risen. This is not surprising as the highest growth rates for corals are found in warmer waters. Further, all the species of corals we have in the GBR are also found in the islands, such as PNG, to our north where the water temperatures are considerably hotter than in the GBR. Despite the bleaching events of 1998 and 2002, most of the corals of the GBR did not bleach and of those that did, most have fully recovered.
Of course, some corals on the Queensland coast are regularly stressed from heat, viz. the remarkable corals of Moreton Bay near Brisbane which are stressed by lack of heat in winter. A couple of degrees of global warming would make them grow much better.
Even the GBR has seen massive changes in its comparatively short life. Eighteen thousand years ago, the GBR did not exist as water levels were about 100m lower than today. At that time, the Australian coast was about 100km from its present position, and the small hills upon which the reefs were to form dotted a broad and flat coastal plain that would become the GBR lagoon. When the sea level started to rise at the end of the ice age, the coast eroded at a phenomenal rate. The Aboriginal people living on these coastal plains lost land at a rate of about 50m each year as they witnessed the birth of one of the natural wonders of the world.
The reef was born in conditions that most biologists would regard as horrific for corals and far worse than what most of the present GBR would see: rising temperatures, high water turbidity due to the erosion, high nutrient concentrations due to erosion and the closer proximity of river mouths, rising CO2 concentrations, and rapidly rising sea levels (10mm per year). These are all factors presently regarded as threats to the GBR.