The impact of Global Warming can be seen all over the world. Global Warming has a major influence on this planet we live on and the ecosystems our planet supports. One ecosystem in particular is going through drastic changes due to global warming and that is the Coral Reefs. Coral Reefs are also known as the rainforest of the sea and contain some of the most diverse creatures in the world. As the temperatures rise globally, so do the ocean temperatures. The increase in water temperatures due to Global Warming is resulting in coral reef bleaching and the overall decline of coral reefs. 

Coral reef bleaching is the product of increased ocean temperatures. Corals only require a sustained temperature increase of one degree Celsius to upset them and cause stress (Worland). Coral bleaching is caused by stress that is triggered from changes in the environment (US Department of Commerce). Environmental stress can come from variations in temperature, light, or nutrients (Warm). This stress causes them to expel the colorful algae living inside of them and leaves the coral with a pale white color (US Department of Commerce). Coral bleaching does not mean the coral is dead, it simply means that the corals have lost their main food and energy source (US Department of Commerce). Bleached coral can recover, but it is a long process that depends on the corals not experiencing any more environmental stresses, such as pollution (Slezak). Bleaching leaves the corals fragile and weak which makes them more prone to disease. Coral diseases make it harder for the bleached coral to recover, and can ultimately result in death (US Department of Commerce). After the coral has died, the ecosystem it supports struggles to survive. The death of the coral allows the reef to be taken over by seaweed (Slezak). The seaweed surrounds the coral and prevents marine animals from using it as a shelter (Slezak). Fish and other animals use corals for both shelter and a food source (Slezak). Once the coral is dead they are forced to move elsewhere to live or end up dying off (Slezak). The effects of the dead coral ripple down through the entire food chain (Slezak). 

Coral bleaching is not an isolated event either. Bleaching events are episodic, and have happened annually since the 1980’s (Baker). The most severe bleaching episodes happen after the corals sit in calm warm water for too long and are usually accompanied by ocean atmosphere-phenomena like El Nino (Baker). El Nino is a surge of warm water that disperses across the Pacific Ocean (Slezak). This phenomenon occurs on irregular intervals, and usually happens once every five years (Slezak). The phenomena of El Nino warms the world and its oceans and therefore extreme bleaching episodes happen during this time period (Slezak). Coral reef bleaching used to be an extremely rare incident. The first recorded bleaching event occurred in 1911 on Bird Key Reef in the Florida Keys (Slezak). Scientists assume that minor bleaching events happened in small patches but were never recorded before this time. The bleaching event in 1911 happened during a time of calm and hot weather (Slezak).  Another small bleaching event was reported in 1929 on the Great Barrier Reef (Slezak). Following this event was a period of silence for the next few decades, until 1979. The first time the term “mass bleaching” was used was in 1979. A bleaching event took place that year hitting the coral reefs from the Florida Keys to the Caribbean (Slezak). This was the first-time coral bleaching was seen destroying large regions rather than small isolated stretches of coral (Slezak). Mass bleaching events have now been recorded every year since. Something that was once rare and unheard of is now being seen every year, and every year the severity of the bleaching events increase (Slezak). 

The Great Barrier Reef is the most well-known coral reef in the world, mainly due to its size. It is the largest coral reef ecosystem on the planet covering more than 133,000 miles. Thousands of unique creatures call it home, including the corals. Almost a quarter of the ocean’s marine life call coral reefs their home (Worland). The importance of the Great Barrier Reef is astounding. Alone, this amazing ecosystem contributes more than 3 billion dollars each year to the Australian economy (Howard). The reef pulls in tourists from all over the world that contribute to the economy (Worland). This reef has been hit particularly hard by the effects of coral reef bleaching. Divers surveying the corals in 2016 discovered that up to 50% of the corals in the reef are dying due to coral reef bleaching (Howard). The northern tip experienced the worst of the die off, due to the hot and still conditions that the corals were forced to sit in for months (Howard). The northern part of the Great Barrier Reef is considered to be the most unspoiled portion of the reef, and this latest bleaching event is the worst to hit this section (Howard). Divers surveying the northern tip found that some atolls had completely died off (Innis). Luckily, a cyclone that reduced ocean temperatures saved the lower part of the reef from the same damage (Innis). Only 1% of the coral in the southern part of the reef has died this year but about two thirds of the coral in the north did not survive this latest bleaching event (Innis).

 In response to the mass bleaching happening here, the Australian Government was forced to issue its highest response level in hopes of stopping this tragedy (Howard). The new level three response requires intense surveying of the reef to be aware of any more bleaching events (Howard). The Australian government also plans on spending around 45 million dollars to clean up the water quality and reduce runoff from farms and industrial sites (Innis). Some people have criticized the Australian government for their plans, pointing out the contradictions of their statements. One of these contradictions is the new Carmichael Coal mine (Innis). This coal mine will be the largest in Australia and its rise is causing huge uproar (Innis). Since coal mines produce large amounts of greenhouse gases that are the main cause of global warming, many people are upset with the creation of a new coal mine (Innis). William Steffen, who is a climate scientist at the Australian National University College of Medicine, Biology and Environment, said this about the new budget “Spending $45 million to improve water quality on the reef is like putting a Band-Aid on a person who has cancer.” Other people have pointed out the insanity of the Australian government for trying to save the Great Barrier Reef, and at the same time creating a new coal mine that ultimately is leading to the death of the reef (Innis). 

Increasing ocean temperatures are a huge problem that coral reefs face, but they are not the only problem causing them stress. Another problem the oceans face due to global warming is increased acidity of the water. Carbon Dioxide is being pumped into our atmosphere at alarming rates, and as more of it is released, more of it dissolves into the ocean (Howard). Increased concentrations of carbon dioxide in the ocean causes the pH of the water to lower, and make it harder for reef building corals to survive (Howard). Nutrient runoff is another problems plaguing coral reefs (Howard). Farms and lawns use industrial chemicals that leak into the ocean and are harmful to the corals (Howard).    

  What is happening to the Great Barrier Reef is just a snapshot of what is occurring all over the globe. Within the last year alone, 12% of the world’s coral reefs have bleached themselves due to extreme heat, and it is predicted that about half of these reefs will not be able to recover and will die (Howard). From Florida to Australia, reefs everywhere are seeing the damages caused by global warming (Worland). Scientists are increasingly concerned because the bleaching events aren’t isolated, rather they are continual, and do not give the coral time to recover (Worland). It is impossible to fully explain the importance of coral reefs. They are home to a quarter of the ocean’s marine life (Worland). They support tourism and fishing industries (Worland). They are extremely helpful during storms, providing protection to coastlines from flooding (Worland). Jennifer Koss, NOAA’s Coral Reef Conservation Program director, explained the situation best, “If you think of corals as canaries [in a coal mine], they’re chirping really loudly right now, the ones that are still alive, that is.”
