When carbon dioxide dissolves into the ocean, it reacts with water molecules to form carbonic acid, lowering the ocean’s pH (and increasing its acidity). This is known as ocean acidification. Since the start of the Industrial Revolution, the pH of the ocean’s surface has dropped from 8.21 to 8.10, resulting in an increase in ocean acidity by about 30%.

Ocean acidification means there will be more hydrogen ions (H+) in the ocean. This is bad as available carbonate ions CO32- will bond with the excess hydrogen, reducing the amount of carbonate ions available for calcifying organisms to build and maintain their shells and skeletons. Examples of these marine life are oysters, clams and corals which are important to keeping the marine ecosystem healthy.

Not only does increased levels of carbon increase the acidity of the ocean, it also cause the ocean (and the rest of the Earth) to become warmer.

Warming oceans, along with ocean acidification, causes coral bleaching, a process whereby corals lose their symbiotic algae which is what gives them their vibrant colours.

In addition, warmer temperatures can cause the ice sheets and ice caps to melt This in turn causes the animals that live there, such as the penguins and polar bears, to lose their habitats and homes.

The melted ice caps and ice sheets will then become water that flows into our oceans and seas, causing rising sea levels that put low-lying islands like Singapore at risk of being submerged.

Changes in Earth’s climate can disrupt ecosystems by altering the water cycle, habitats and animal behavior (eg. nesting, migration pattern). Some of these changes are irreversible. While plants and animals have adapted to environmental changes over millions of years, human-induced climate change is going at a larger and faster scale, thus increasing the risk of some species going extinct.

The extinction of species is dangerous can it has wider implications on the food chain and ecosystem. For example, the extinction of a predator removes a check and balance in the food chain, causing prey populations to explode and further tipping the food web and ecosystem off-balance.