Travel to Australia’s Great Barrier Reef with Joshua Jackson, and witness the beauty of a fragile reef ecosystem that could be lost if people continue to release carbon dioxide (CO2) into the atmosphere at current levels.

In a conversation with a University of Queensland marine biologist, Jackson learns how science has only recently connected climate change with ocean acidification. The ocean absorbs CO2 from the atmosphere and the CO2 reacts with seawater, increasing the ocean’s acidity. Higher acidity is harmful to coral and other marine life. Though humans have assumed that our vast ocean is an inexhaustible resource, it appears the ocean’s resilience is reaching its limit.

Find more of this story in the “Collapse of the Oceans” episode of the National Geographic Channel’s Years of Living Dangerously series.

Although coral reefs make up less than one percent of the ocean floor, they support a quarter of all marine species.

Human activity that adds CO2 to the atmosphere also warms the oceans, which can cause coral bleaching. When the water is too warm, coral releases the algae that give it its color. The coral then turns white and often dies.  

Most coral reefs grow in tropical waters. The largest coral reef is the Great Barrier Reef, one of the “Seven Natural Wonders of the World,” which extends more than 1,930 kilometers (1,200 miles) off the eastern coast of Australia.

The continental United States has one barrier reef, the Florida Reef, stretching about 555 kilometers (345 miles) from Palm Beach to beyond Key West. The Florida Reef is important to the local and state economy, generating about $6.3 billion annually in tourism.


to become more acid.

coral bleaching

loss of symbiotic algae (zooxanthellae) in corals, leading to a loss of pigmentation.

coral reef

rocky ocean features made up of millions of coral skeletons.


community and interactions of living and nonliving things in an area.


ability to recover from something.


the industry (including food, hotels, and entertainment) of traveling for pleasure.