Coral reefs, which cover about 280,300 square kilometers of the world’s oceans, will likely disappear by the end of this century, according to a new book released today by a top United Nations scientist, reports The Independent.This would be a new first for mankind, in which an entire ecosystem is eliminated from the Earth by human activity.
The fragile coral ecosystem is mainly under threat from climate change and ocean acidification, though overfishing, water pollution and urban development have also also attributed to the reefs’ decline.
From The Independent:
Carbon emissions generated by human activity, especially our heavy use of fossils fuels, are the biggest cause of the anticipated rapid decline, impacting on coral reefs in two main ways. Climate change increases ocean surface temperatures, which have already risen by 0.67C in the past century. This puts corals under enormous stress and leads to coral bleaching, where the photosynthesising algae on which the reef-building creatures depend for energy disappear. Deprived of these for even a few weeks, the corals die.
On top of this comes ocean acidification. Roughly one-third of the extra carbon dioxide we put into the atmosphere is absorbed through the ocean surface, acidifying shallower waters. A more recently recognised problem in tropical reef systems, the imbalance created makes it harder for reef organisms to retrieve the minerals needed to build their carbonaceous skeletons. “If they can’t build their skeletons – or they have to put a lot more energy into building them relative to all the other things they need to do, like reproduce – it has a detrimental effect on the coral reefs,” says Paul Johnston of the University of Exeter, and founder of the UK’s Greenpeace Research Laboratories.
Despite occupying less than one tenth of one per cent of the oceans, coral reefs are home to about a quarter of all marine species. They are often referred to as “rainforests of the sea” due to their immense biodiversity. Some 275 million coastal residents who depend on coral reefs for their livelihood and nutrition will also be affected if the marine structures become extinct.
NOW WATCH: Briefing videos
Business Insider Emails & Alerts
Site highlights each day to your inbox.