<Table> <Tr> <Td> </Td> <Td> The examples and perspective in this article deal primarily with the United States and do not represent a worldwide view of the subject . You may improve this article, discuss the issue on the talk page, or create a new article, as appropriate . (May 2012) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> The examples and perspective in this article deal primarily with the United States and do not represent a worldwide view of the subject . You may improve this article, discuss the issue on the talk page, or create a new article, as appropriate . (May 2012) (Learn how and when to remove this template message) </Td> </Tr> <P> Coastal Hazards are physical phenomena that expose a coastal area to risk of property damage, loss of life and environmental degradation . Rapid - onset hazards last over periods of minutes to several days and examples include major cyclones accompanied by high winds, waves and surges or tsunamis created by submarine earthquakes and landslides . Slow - onset hazards develop incrementally over longer time periods and examples include erosion and gradual inundation . </P> <P> Since early civilisation, coastal areas have been attractive settling grounds for human population as they provided abundant marine resources, fertile agricultural land and possibilities for trade and transport . This has led to high population densities and high levels of development in many coastal areas and this trend is continuing into the 21st century . At present, about 1, 2 billion people live in coastal areas globally, and this number is predicted to increase to 1, 8--5, 2 billion by the 2080s due to a combination of population growth and coastal migration . Along with this increase follows major investments in infrastructure and the build environment . </P>

Identify and describe three of the challenges facing coastal environments in the 21st century