One third of the world's population lives on the coast, which covers just 4% of the world’s surface. This land is constantly being reshaped by wind and waves. Coastal forests protect inland areas from storm surges and prevent silt from clogging waterways.
Coasts are natural fisheries, rich in biodiversity and natural resources. These areas provide everything from medicines to building materials, so they are vital to the global ecology and economy. Coastal beach sand is mostly quartz silica but comes in different colors depending on the kind of sediment being deposited. Finer sediment is often found on beaches protected from wind and waves.