Coral reefs are colorful underwater forests which teem with life and act as a natural protective barrier for coastal regions. The fishes and plants which call them home belong to some of the most diverse – and fragile – ecosystems on the planet.Global warming is affecting coral reefs because:Studies show that warmer-than-normal sea temperatures are contributing to coral bleaching, which has been on the rise in recent years, weakening and killing reefs in many parts of the world.Sea level rise caused by melting sea ice and thermal expansion of the oceans could also cause problems for some reefs by making them too deep to receive adequate sunlight, another factor important for survival.Higher levels of carbon dioxide in the atmosphere are changing the chemistry of the oceans, making it more difficult for corals to build up calcium carbonate skeletons.In one year alone, sixteen percent of the world’s coral reefs were wiped out. A sea temperature change of a mere one degree Celsius would yield similar losses. Increasing levels of carbon dioxide in the water cause additional damage to corals, leaving them defenseless against storm damage and erosion.To help draw attention to the problem, NWF has launched a public awareness campaign targeted at divers and snorkelers to arm them with information about how they can help protect coral and minimize global warming’s impact. Some of the most important actions recommended by NWF include:Never anchor on a reef. Volunteer with organizations working to clean up local waterways. The health of all waterways — rivers, lakes and bays — ultimately affects the ocean. Slow global warming by conserving energy, which includes using energy-efficient lighting and appliances and using mass transportation whenever possible.