Chasing Coral – A Netflix Documentary

Chasing Coral


“Chasing Coral” is a gloomy but surprisingly hopeful film on the topic of coral bleaching and how climate change has escalated its impact in recent years. The director, Jeff Orlowski, also produced a film on climate change’s impact on arctic glaciers called “Chasing Ice” (2012). Orlowski even brings a few of the main cast members from his previous documentary to illustrate how climate change is a global issue. The film begins with shots of coral reefs and a monologue from Richard Vevers stating how vital coral reefs are for not only to marine life but for millions of humans as well. Vevers, concerned about the health of the reefs, started The Ocean Agency after working in advertising for many years. Vevers grew worried with the deterioration of coral reefs when he noticed that sea dragons were disappearing from his favorite spots. The goal of Vevers’ organization and this film is to better educate the public on coral reefs. He has and continues to work on doing just that by “bringing google street-view underwater” with a specially designed 360 degree camera that captures images every 3 seconds.

However, Vevers wanted to better illustrate coral bleaching and how quickly its impacts can take place, so a team of scientists and hobbyists came together to develop a way to make time-lapse cameras capable of staying underwater for four months without human interaction. Due to the intense pressure being so far underwater and other factors like hurricanes, the setup had to be very sophisticated to handle a plethora of issues. The team was able to develop the technology and set the cameras up in troubled spots in Hawaii, Bermuda, and the Bahamas. However, the team still ran into issues later on when retrieving the images. Despite setting the cameras onto manual focuses, all of the cameras became out of focus sometime when they were underwater making the footage useless. This required the team to come back together to find a way to prevent the cameras from becoming out of focus again, which was done by adding new lens to the cameras. The team then set out for new troubled locations along the Great Barrier Reef in Australia near Keppel Island and Huron Island. Fortunately for the reefs, a series of thunderstorms and a tropical cyclone brought cooler water to the region preventing a bleaching event.

Unfortunately for the team, this meant that they were not going to capture a bleaching event anytime soon. However, they received tips from residents on Lizard Island and New Caledonia that reefs in the area were undergoing a “strange event” so the teams quickly left their posts abandoning their time-lapse cameras. Instead, the time-lapse was recorded manually by having a scuba diver, like Zachary Rago, dive to the reefs every day and take pictures at several set spots everyday for several months. Rago and other divers were successfully able to obtain enough footage to show how coral bleaching destroyed the reefs within months. The footage was disheartening, but it effectively showed how coral bleaching can destroy an ecosystem in a relatively short amount of time. The documentary also concludes by stating that this is a global issue and shows videos of people all over the world sharing their experiences with coral bleaching.

Comparison photo shown in film showing a healthy reef becoming bleached.

The film ultimately states that the increased concentration of CO2 in the atmosphere due to the burning of fossil fuels is the main culprit behind the increased mass bleaching events. Animations and illustrations were used to show how this is the case. When fossil fuels are burned, they emit a gas called carbon dioxide (CO2), one of several greenhouse gases present in the atmosphere. Greenhouse gases help to keep heat trapped in the Earth’s atmosphere or otherwise the Earth would be too cold for survival. However, since there is a higher concentration of greenhouse gases in the atmosphere now, more heat is being deflected back to the ground. The ocean has a very high heat capacity, so this excess heat is mostly being absorbed by the oceans making them warmer. Unfortunately for coral reefs, they are not resilient to an increase in temperature so they begin to experience effects rather quickly. Raising surface ocean water temperatures 2 degrees Celsius (roughly 4 degrees Fahrenheit) can be enough to significantly impact and even kill certain reefs. Fluctuations in surface ocean water temperature is another normal natural phenomenon, but scientists feel that the recent upwards trend and the rate at which its increasing is to be blamed on greenhouse gases.

Coral Bleaching and Warming Oceans

Recorded sea surface temperatures compared to average between 1880-2015.

While coral bleaching is a natural phenomenon, the increased occurrence of widespread bleaching events in recent years has scientists all over the world worried about the future. With oceans continuing to warm on average, projections show that average surface sea temperatures could rise to the point it could support the mass extinction of coral reefs within our lifetime according to the documentary. How much sea surface temperatures will rise can be predicted and modeled, but it does not mean that they will come into fruition. In fact, the National Oceanic and Atmospheric Administration (NOAA) provides several projections in the documentary on how much their experts believe sea surface temperatures will rise. One projects shows a linear path of rising temperatures while others show temperatures rising then leveling off at some point between now and 2100. There are many factors that can affect global sea surface temperatures, so it is not surprising that scientists cannot say for sure how much further the oceans could warm if greenhouse gases continue to be added to the atmosphere.

El Niño’s Impact?

Sea surface temperatures 2015-2016 showing strong El Niño event taking place.

The documentary also points out that in 2016, 29% of the Great Barrier Reef was killed off due to a massive coral bleaching event.  It is actually not too surprising that the Great Barrier Reef suffered so much in 2016, as a prolonged and very strong El Niño event was taking place for much of 2015 and into 2016. An El Niño occurs when warm water (usually 0.5 Celsius above average or higher) appears off the coast of Ecuador and Peru or along the equator in the Pacific Ocean usually during the winter. This warmer water impacts the global atmosphere resulting in adverse effects in different portions of the world. When an El Niño event is taking place, portions of the Northern Great Barrier Reef usually see dry and warm conditions which can aggravate coral bleaching episodes. Climate change could elevate the impacts of El Niño, but otherwise El Niño is a naturally occurring phenomenon that impacts the global sphere usually every couple years.


In conclusion, this documentary really helped me understand the issue of coral bleaching and how it can affect the human population as well. I personally knew about the issue of coral bleaching but I did not know how bad it actually was. The film is ultimately right about how this is also an issue of public knowledge and that a better way of communication is needed between scientists and the public. The organization has a website that I highly recommend checking out if you would like to get involved at:


This film can be viewed on Netflix here:

More information on El Niño:

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