Spectacular death of corals might make it easy to convince the world that the Great Barrier Reef (GBR) is in trouble, but it is even more powerful if you can claim that “it never happened before 1960”. For the GBR, we knew very little before 1960, so it is easy to say that this spectacular death was unknown before the 1960s.
Large parts of Australia, especially the tall forests of Victoria and New South Wales, occasionally have very destructive fires where every tree is killed. Perhaps the best example is the Mountain Ash forests, some of the tallest trees on the Earth, which are utterly destroyed by the occasional bushfire. The forest takes decades to recover, far longer than the GBR takes to recover from, for example, a plague of starfish. In addition, these massive events are necessary for the forest ecosystem, which has adapted to the cycles of sudden destruction and slow recovery.
A scientist would never claim that bushfires “never happened” before the 1960s, as is often said of coral bleaching and starfish plagues, because it is well-known that bushfires have always occurred. Captain Cook, when he explored the east coast of Australia in 1770, saw many fires; the early pioneers documented huge bushfires. We now also appreciate how Aboriginal people used fire to manage and modify vegetation to their liking. Every Australian accepts fires as part of being Australian. There is an argument that the fires are worse today than in the past, but there is no doubt that there have always been massive bushfires.
The situation for the GBR is totally different. Being underwater, it was hidden from view until the 1960s, so there is much less anecdotal information than for land ecosystems.
Until around 80 years ago, most of the underwater world was almost as inaccessible to the general population and scientists as Mars or Venus is today. But two inventions have revolutionised accessibility – SCUBA equipment in the 1940s, and the outboard motor which started to become common in the 1960s. Together with the growth in tourism, also in the 1960s, marine science boomed. It is not a coincidence that the first scientific observation of plagues of coral-eating crown-of-thorns starfish (COTS) was in the 1960s on Green Island, the site of the first major GBR tourist destination. Green Island is one of the few locations where the GBR gets close to the mainland (25 km), making it easily accessible from Cairns.
Crown-of-thorns starfish was the first big scare where the world was told that the GBR was facing a dire future. The world was told that these plagues never occurred before the 1960s and that they must have been caused by human activity. But the question must be asked, if a starfish outbreak occurred in 1920, who would have noticed? Would the fact have been reported? And to whom would it have been reported? And would anyone have been interested? Until the 1960s the only visitors to the GBR were hardy fishermen and sea-cucumber harvesters. They may have noted the loss of coral and some, with the very primitive diving equipment of the time, might have noted large numbers of COTS.
North Queensland was a very remote place in the 1920s. So, what would a fisherman do after discovering a crown-of-thorns starfish outbreak? The hardy fisherman was likely almost illiterate and would not know of any scientists and may not even be aware of the existence of the closest university in 1920, which was 1500 km from most of the GBR. This was an incredibly remote part of the world. Just to the north of the GBR is the rugged highland plateau at the centre of the island of New Guinea, the large human population of which would not be discovered until the 1930s when aircraft surveying that isolated mountain area made contact for the first time. It is hardly surprising that if Europeans did not notice a large and thriving population of people living on a highland plateau, they might also not have noticed a bit of coral death. It would be even more surprising if they cared in the 1920s.
But by 1960 the University of Queensland had established a college in Townsville adjacent to the GBR; this later became James Cook University (JCU), a world leader in coral research. In 1970 there were still only half a dozen marine scientists on the GBR coast (at JCU). The Australian Institute Marine Science (AIMS), also in Townsville, was established in 1972 but only became a significant institution when its present laboratories were built in the late 1970s. By the early 1980s, JCU and AIMS had around 200 staff. Expansion of science on the GBR continued and today there would be thousands of scientists with some interest in the GBR.
It is very notable that there are three very spectacular types of event that occur frequently on the GBR and they have all been discovered by science only very recently. These are starfish plagues, discovered in the 1960s; mass coral bleaching events where corals are killed by hot water, discovered late in the 1970s; and mass coral spawning events, discovered in the 1980s. This latter event is where virtually every coral on the GBR simultaneously releases eggs forming massive slicks of pinky-white material that float on the water surface. These slicks are so big that they can be detected with satellites.
Scientists claim that the starfish plagues and mass bleaching, which kill coral, are caused by humans and did not occur before European settlement. But, for some reason, the massive spawning events, which were never observed before 1980, are a wonder of nature. In this inconsistent story, corals are allowed to reproduce but never die before 1960. In reality, little was known about the GBR before that date – not even these massive spawning events which would undoubtedly have been well-known to early European fisherman and Aboriginal people.
IT IS useful, at this stage, to review the various threats the world is told have despoiled the GBR and tp state, briefly, why they have been exaggerated. These threats to the GBR are well-documented in important government publications such as the 2019 GBR Outlook Report.
Mud from farms: It is asserted that sediment (mud) washed down rivers from farms is smothering the GBR. There is good evidence to suggest that the quantity of sediment eroded from the land is considerably greater than before European settlement. There is no evidence, however, indicating that this sediment has affected the GBR significantly.
There is almost no sediment from the land on the GBR. It almost never reaches the GBR in quantities that could have any adverse impact on the coral. Some of the reefs very close to the coast, the Inshore Reefs, which are about one percent of the coral of the GBR, very occasionally have slightly elevated amounts of sediment in the water, and are only very marginally affected.
Farm fertiliser: It is claimed that farm fertilisers, mainly in the form of nutrients nitrogen and phosphorous, cause starfish plagues.
These nutrients almost never reach the GBR in significant quantities from rivers. The link between starfish plagues and fertilisers is extremely tenuous and disputed by many experts on starfish plagues. There are far greater natural movements of the nutrients across the seabed than come down the rivers.
There is a massive flow of water into and out of the GBR from the Coral Sea that rapidly dilutes any increased nutrients from the coast. In fact, as much water comes into and out of the GBR from the ocean in eight hours as comes down all the rivers combined in a whole year. It is virtually impossible for farms to pollute the GBR significantly (see chapters 3 and 6).
Pesticides from farms: Pesticides that come from agriculture are never found in elevated concentrations on the GBR. Most of the time they are completely undetectable even with the most sensitive equipment. Occasionally pesticides are detected in very low concentrations close to the shore, well away from the GBR. Pesticides are an irrelevance to the health of the GBR.
Sediment from dredging ports: The quantity of sediment dredged from ports is even less than comes down the rivers, and similarly irrelevant to the health of the GBR. In the last 25 years, surveys of corals close to dredging have repeatedly shown that no loss of coral has occurred.
Climate change: The modest temperature increase of around 0.5-1.0o C during the twentieth century has probably resulted in a slight increase in growth rate for coral on the GBR. It is well established that corals generally grow faster in warmer water and most of the corals of the GBR also live in waters around Thailand, Indonesia and Papua New Guinea where the water is considerably hotter than the GBR, and they grow in some cases almost twice as fast.
It has been claimed that the bleaching events, caused by unusually hot weather, have killed huge amounts of coral. But they are almost certainly entirely natural and the loss of coral has been greatly overstated in every case. In addition, recovery from bleaching has been very strong and rapid.
Climate change – increased CO2 and lower pH: Of all the threats to the GBR, this is the one that has some credibility. Some experiments conducted on corals where increased concentrations of CO2 have resulted in slower growth rates.
These experiments are provisional and should not, as yet, be regarded as conclusive. There is also considerable conflicting evidence.
To get the science wrong is not a victimless crime
If scientists are making a succession of major mistakes about the GBR, it is not without consequences. This is not some abstract argument between academics in their ivory tower. Every major industry in north-eastern Australia is affected by legislation designed to “save the Reef ”; the costs run into billions of dollars. The Queensland State Government introduced draconian legislation in December 2019 placing far tighter restrictions and burdens on agricultural industries.
Every major aspect of farm activity is now tightly controlled by bureaucrats. Output of the sugar industry is being reduced due to restriction on the quantity of fertilisers farmers can use. The cattle industry has regulations affecting application of pesticides and on clearing of regrowth trees in pastures. There are also continuous calls by environmental activist groups to restrict the mining industry to “save the Reef ”, especially coal mining. All the bad publicity claiming that the GBR is in terminal decline is affecting the tourist industry. The world thinks the GBR is almost dead, so why bother visiting?
The science of the GBR is thus a critical question for the people of north-eastern Australia. Mistakes have consequences and there is no excuse for carelessness, unverified methodology, or inadequate checking.
Even if it is accepted that the GBR is in serious peril, there are still very good reasons to ensure that all the science is correct. This is because there are only finite resources and a large number of supposed threats. Not all threats are going to be equally important and they must be prioritised to ensure value for money for any remediation measures that might be funded. Money should not be wasted fixing a problem that does not exist, while a real problem gets less attention than it deserves.
The GBR should be treated with respect; no significant damage to the Reef is tolerable. But, if the GBR is actually in good shape, then it means the focus of worry, and attention, should move to something else instead. Something that is a genuine problem. Something that must be fixed. Humans seem to have only a finite capacity for care, compassion, and concern. If we are worrying more about the GBR, we will likely be worrying less for the fate of the Borneo rainforest or some other natural treasure.
Peter Ridd’s Reef Heresy: Science, Research and the Great Barrier Reef is published by Connor Court and can be ordered by following this link