Some of the world's most beautiful beaches are right here in Hawaii but researchers say that could all change due to rising sea level if changes aren't made soon.

"Sea walls keep getting approved and they lead to beach narrowing and beach loss," Prof. Chip Fletcher, UH Manoa, said. 

Researchers studied that narrowing along a five-mile section of Oahu's Windward side, results found over the course of 87 years, 20 percent of beach length has been lost and 55 percent of beaches have narrowed. 

"If you want to protect beaches, you can't compromise. We have to get out of the way of the rising ocean," Fletcher said. 

In 1972, congress enacted the U.S. Coastal Zone Management Act to preserve and protect the nation's coastal zone. Five years later, the Hawaii Coastal Zone Management Program was established for state and local agencies to oversee that law.

Fletcher says government agencies allow certain property owners threatened by erosion to build sea walls and other shoreline armoring.

"A wall does not move and a beach needs to move when sea level's rising. So, there are these misunderstandings and common misconceptions that are still present in the people's minds who are issuing these permits. Our environmental agencies need to start acting like they are going to protect the environment... There seems to be a lack of scientific training for the people who are tasked with approving permits," Fletcher said. 

In a statement, Josh Stanbro with the Office of Climate Change, Sustainability and Resiliency says:

"Mayor Caldwell and his administration have been leading on climate change issues and closely following the new science. In fact, the city-wide directive the mayor issued on July 16 anticipated this study and ordered departments to be more pro-active about factoring this information into upcoming coastal decision making. While the city currently discourages any variance requests, applications for coastal armoring variances are being submitted. These applications will need to emphasize alternatives to any armoring in order to mitigate negative impacts on adjoining landowners and public beaches. The mayor's directive makes it clear that a rapidly changing environment requires a new look at setback standards and other policies to protect public benefit and public safety for the citizens of Oahu."

Sam Lemmo with the Department of Land and Natural Resources says one way to help is strengthen Hawaii's Coastal Zone Management Act. 

"Including stronger language in the act regarding beach conservation and protection of public access to these areas so that when the county agencies are faced with the dilemma of having to consider a sea wall over the loss of private property, they have stronger support from the state policies towards the preservation of the beaches," Lemmo said. 

Lemmo says it's a real possibility that some beaches could disappear in as little as 50 to 60 years.