Diwei Xiao Professor Watanabe Marine Biology 5 December 2022 What effect will the climate crisis have on the Great Barrier Reef? The Great Barrier Reef is located in Queensland, Australia. It is the biggest coral reef system in the world. It has more than 2900 individual reef systems and 900 tropical islands. The Great Barrier Reef is also one of the seven wonders of nature. Also, it is larger than the Great Wall in China and making it become the one and only living thing that can be observed from outer space. From a financial perspective, the Great Barrier Reef has contributed a lot. Because it has attracted millions of people to come and visit, which makes tourism highly developed. From a biological perspective, the Great Barrier Reef provides enormous value for scientists to study the coral reef system. However, according to research, the climate crisis like temperature rising is now threatening the Great Barrier Reef mainly by causing coral bleaching, ocean acidification, etc. And there are more scientific studies that can support these problems that might be getting worse in the future. “Climate change is the greatest threat to the Great Barrier Reef and coral reefs worldwide. Climate change is caused by global emissions of greenhouse gases, such as carbon dioxide from the burning of fossil fuels (coal, oil and natural gas), agriculture and land clearing. Not only has the current concentration of carbon dioxide in the atmosphere reached record levels in the last 800,000 years, the climate is changing at a rate unprecedented over decades to millennia.”(Australian Government 2019) The effects of the climate crisis on the Great Barrier Reef are severe. Because there are two types of ways that could have impacted the Great Barrier Reef, the external way and the internal way. The external way is the effect that the climate crisis has on weather which can cause secondary impacts on the Great Barrier Reef and the ocean. For instance, storms, floods, etc. “Coral reefs, seagrass meadows and islands have a natural resilience to physical disturbances from weather events such as storms and cyclones. However, climate change-induced shifts in weather patterns that affect the frequency, intensity or distribution of these disturbances will have important implications.” (Zell, pg. 56) To examine this statement, there are some research can be provided. “Cyclones were responsible for 48 percent of coral loss recorded by the Australian Institute of Marine Science’s Long-term Monitoring Program between 1985 and 2012. Between 2004 and 2018, 10 cyclones of category three or greater crossed the Great Barrier Reef Marine Park. Impacts were most severe in the southern half of the region, causing significant damage to coral reef habitats.”(Australian Government 2022) According to these two reports, it is easy to conclude that the external way or secondary impacts caused by the external way can cause severe damage to the Great Barrier Reef. And the frequency and intensity of serious weather events are becoming more often and stronger as time past. Also, damage caused by the external way will take decades, even hundreds of years for the coral reef system and structure to recover. Thus, it is promising to say the damage that the climate crisis will have on the Great Barrier Reef by the external way is going to be worse and more often in the future. The internal way is another way that has been mentioned. It is the effect that the climate crisis has on the Great Barrier Reef and the ocean, such as coral bleaching, ocean acidification, etc. It is also the main way to impact the Great Barrier Reef. Coral bleaching is one of the major problems that has a strong connection with climate change. “When water is too warm, corals will expel the algae (zooxanthellae) living in their tissues causing the coral to turn completely white. This is called coral bleaching. When a coral bleaches, it is not dead. Corals can survive a bleaching event, but they are under more stress and are subject to mortality.”(NOAA 2010) The lucky point of this unlucky thing is if the water temperature can decrease, the coral reef will be able to return to normal. But it means that fixing climate change is the only way to solve this problem. “Sea surface temperatures have increased by an average of 1.05 °C since 1900. This has led to an increase in the frequency of extreme heat events over land and sea.”(Australian Government 2022) For the past one hundred years, the issue of temperature rising has not been solved and it kept becoming worse, so with a reasonable assumption, in the future, the coral bleaching problem will still remain or even get worse. Ocean acidification is also one of the major problems that are highly related to climate change. “Acidification occurs because the ocean acts as a carbon sink, absorbing carbon dioxide from the atmosphere. This changes the ocean's chemistry by reducing the ocean's pH — which measures acidity or alkalinity — over an extended period. When seawater absorbs carbon dioxide, chemical reactions occur, resulting in a greater concentration of hydrogen ions. This causes the seawater to become more acidic and carbonate ions to be relatively less abundant. Carbonate ions are the building blocks for many marine animals such as corals, oysters, clams, sea urchins, molluscs, crustaceans and echinoderms, helping them to produce shells and skeletons.”(Australian Government 2022) For the Great Barrier Reef, ocean acidification weakens the coral reef's ability to build skeletons and coral structures. Also, this will impact other marine creatures who take the Great Barrier Reef as protective habitat. More importantly, this could slow the coral reef growth rate and make it harder for the corals to recover from other problems such as coral bleaching, damage caused by serious weather events, etc. Therefore, combine these facts with the report which says “oceans around Australia are acidifying and have warmed by more than 1 °C since 1900, contributing to longer and more frequent marine heatwaves.”(Australian Government 2022) It is not hard to tell that the effects of temperature rising and ocean acidification might magnify each other. Due to these reasons, it is possible to say that ocean acidification will have more and stronger impact on the Great Barrier Reef. Overall, based on research, the effects that the climate crisis will have on the Great Barrier Reef are unpredictable weather events that could cause serious damage to it, worse and more coral bleaching issues which make the coral reefs more vulnerable, ocean acidification, and other harmful problems that can be caused by these problems. The solution for these effects is simple to think of but hard to take action on. By decreasing global greenhouse gas emissions, the temperature rising issue will be solved and it will make the coral reefs faster in recovery. All people in the world should try hard to protect the environment because it is our responsibility. Bibliography G.B.R.M. P. A., Australian Government (2019). Climate change. gbrmpa. Retrieved December 5, 2022, from https://www2.gbrmpa.gov.au/learn/threats/climatechange#:~:text=Increasing%20global%20temperatures%20will%20cause,for%20r ecreation%20and%20their%20livelihoods Zell, L. (2012). The Great Barrier Reef: A journey through the world's Greatest Natural Wonder. Murdoch. G.B.R.M. P. A., Australian Government. (2022). State of the climate 2022. State of the Climate 2022: Bureau of Meteorology. Retrieved December 5, 2022, from http://www.bom.gov.au/state-of-the-climate/ US Department of Commerce, N. O. and A. A. (2010, March 15). What is coral bleaching? NOAA's National Ocean Service. Retrieved December 5, 2022, from https://oceanservice.noaa.gov/facts/coral_bleach.html#:~:text=When%20water%2 0is%20too%20warm,and%20are%20subject%20to%20mortality.
