The Great Barrier Reef is known as the largest coral reef system in the world, composed of over 2,900 individual reefs and 900 islands stretching for over 2,300 kilometres over an area of approximately 344,400 square kilometres. The reef is located in the Coral Sea, off the coast of Queensland, Australia. It has recently been revealed that the condition of this Great Barrier Reef is very bad, and this so-called global icon, in addition to the already known threats of global warming, is threatened with over 40 more dangers. It is true that global warming and poor water quality are major threats, but other threats, which are often thought not to be so harmful or not fully understood, should also be seriously addressed.
The Great Barrier Reef Marine Park Authority produced the 2019 Outlook Report, required by law every five years. It shows the total number of threats has increased from 41 in 2014 to 45 now. All of these threaten the Great Barrier Reef’s World Heritage values - the factors that make it globally outstanding. Of the 45 threats, 42 threaten its remarkable ecosystem.
Some of the new threats are potential negative impacts of genetic modification that are not sufficiently understood, but could appear as a threat after the release of genetically modified organisms into the wild. The table below shows the most alarming 21 risks to the Great Barrier Reef ecosystem. It is becoming clear that many of the risks are serious, and the situation is getting worse.
The likelihood and consequences of many lesser known threats are increasing.
The ten threats leading to “very high” risks are of greatest concern, especially as all are considered “almost certain” to occur. They include:
The modification of coastal habitats from continued urban and industrial development. Vegetation clearing damages important ecosystem services for many marine species.
Illegal fishing and poaching elsewhere are impacting global fish stocks. This will increase the incentive for such activity on the Great Barrier Reef, with major consequences for some species and habitats.
Altered weather patterns are predicted as climate change accelerates, including more frequent and/or intense cyclones, floods and heatwaves. These weather events are natural processes in tropical regions, but when severe can prolong recovery times of coral ecosystems by up to 20 years.
At least 6 of the 11 “high” risks are worsening, including:
Disease outbreaks in corals, turtles and coral trout were of “minor” consequence in 2009 but “major” consequence in 2019.
The likelihood of altered ocean currents and their flow-on effects has been revised from “unlikely” in 2014 to “almost certain” in 2019. An increase in speed and the southern extent of the East Australian Current has already been observed. Such changes could irreversibly affect how eggs, larvae and juvenile organisms are naturally distributed.
The likelihood of problems from artificial light emitted from shipping and coastal development has increased from “likely” in 2014 to “almost certain” in 2019. This is known to affect turtle hatch lings and may be detrimental to seabirds and fish behaviour.
Many of the threats to the reef ecosystem occur simultaneously, and can act together to exacerbate the impacts. These cumulative effects are not all well understood and have not been adequately addressed in the Outlook Report, so this is further cause for concern.