Ocean Threats

Human activities are threatening the health of the world's oceans. More than 80 percent of marine pollution comes from land-based activities. From coral bleaching to sea level rise, entire marine ecosystems are rapidly changing.

Global warming is causing alterations in ocean chemistry and many oceanic processes, and it is threatening many species of marine animals that cannot cope with higher temperatures. Overfishing is a serious problem in many parts of the world. Conservationists advocate creating expansive marine reserves to protect the biodiversity of the oceans.

Threats

• Global warming is causing sea levels to rise, threatening coastal population centers.
• Many pesticides and nutrients used in agriculture end up in the coastal waters, resulting in oxygen depletion that kills marine plants and shellfish.
• Factories and industrial plants discharge sewage and other runoff into the oceans.
• Oil spills pollute the oceans, though U.S. water-sewage treatment plants discharge twice as much oil each year as tanker spills.
• Air pollution is responsible for almost one-third of the toxic contaminants and nutrients that enter coastal areas and oceans.
• Invasive species such as poisonous algae, cholera, and countless plants and animals have entered harbor waters and disrupted the ecological balance.
• The United Nations Food and Agriculture Organization estimates that 31.4 percent of fish stocks are either fished to capacity or overfished.

Solutions

• Establish marine parks to protect biodiversity.
• Reduce destructive fishing practices such as trawling.
• Minimize the use of military sonar that can harm or kill whales and other marine mammals.
• Help fishers to maintain their livelihoods by incorporating conservation efforts.
• Install measures to reduce the amount of fish caught accidentally.