Oceans cover 71% of the Earth's surface. Discussions about climate change often seem to focus on what's happening in our atmosphere, but many changes are happening in our oceans. The oceans have absorbed 90% of the excess heat and 28% of the carbon pollution generated by human consumption of fossil fuels (Nuccitelli 2015). The purpose of this article is to show how the effects of climate change are affecting the coral reefs of our oceans, with a focus on the coral reef systems of the Caribbean and the Great Barrier Reef. It is well known that Caribbean coral reefs suffered more damage between the two reef systems. That’s not to say the Great Barrier Reef hasn’t suffered its own damage. He has suffered and will continue to suffer in the future. Corals use these products to make proteins, fats and carbohydrates, as well as to produce calcium carbonate. Calcium carbonate is what coral uses to make its hard skeleton. The world's coral reefs are of great importance because they are home to 25% of all marine life on the planet. Now that corals have been briefly described, we can understand why the effects of climate change are damaging coral reef systems. Ocean acidification is one of the consequences of climate change. Acidification is caused by an increase in carbon dioxide in our oceans and leads to a decrease in the pH of marine waters. This decrease in pH reduces the ability of corals to build their hard skeleton. Coral calcification rates on the Great Barrier Reef and many other reef systems around the world have declined by 15–20% since 1990 due to increasing thermal stress (De'ath 2012). It has already been mentioned that the oceans absorb almost all of the excess heat caused by climate change. This affects coral reef systems in what is known as coral bleaching. The term bleaching refers to the loss of coral colors. The color of a coral is the result of the zooxanthellae present. When the water gets too hot,