By 2020, the number of people living along the U.S. coast will increase from 123 million to 134 million, according to a latest report from NOAA, with input from the U.S. Census Bureau. The increase in population of the coast means that more people will be affected by future storms.

The shoreline accounts for less than 10 percent of the land available in the U.S. (excluding Alaska) and the new report has found that at least 39 percent of the U.S. population lives in counties directly on the coastline. The data for the report came from the 2010 census.

Also, more than 52 percent of the U.S. population lives in counties that drain into watersheds. A watershed is a place where water and sediments drain into a large water body like ocean or bay.

The increase in population not only affects people and property, but also affects the ecosystem of the region.

The coast, being the center for trade and commerce, has been the most sought-after places to live, not just in the U.S., but also the world. According to UN Atlas of Oceans, about 44 percent of the world's population lives within 150 kilometers (93 miles) of the coast.

The world's shorelines are ecological hotspots. Of the 13,200 known species of marine fish, about 80 percent live in the coastal regions.

"As more people move to the coast, county managers will see a dual challenge -- protecting a growing population from coastal hazards, as well as protecting coastal ecosystems from a growing population," said Holly Bamford, Ph.D., assistant NOAA administrator for the National Ocean Service, in a news release.

This is the first time that the report differentiates between counties that drain into watersheds called the Coastal Watershed Counties and counties that border the coast (including the Great Lakes).

About 769 Coastal Watershed Counties and 452 Coastal Shoreline Counties, which lie directly on the shoreline, were included in the study.

The report found that between 1970 and 2010, the population of Coastal Shoreline Counties increased by 39 percent, while there has been an increase of 45 percent in the Coastal Watershed Counties' population.  

"Whether you're talking about watershed counties or shoreline counties, the coast is substantially more crowded than the U.S. as a whole. Population density in shoreline counties is more than six times greater than the corresponding inland counties. And the projected growth in coastal areas will increase population density at a faster rate than the country as a whole," said Kristen Crossett of NOAA's National Ocean Service and editor of the report.