{"id":19443,"date":"2013-09-10T10:30:49","date_gmt":"2013-09-10T20:30:49","guid":{"rendered":"http:\/\/www.hawaii.edu\/news\/?p=19443"},"modified":"2020-08-17T14:56:26","modified_gmt":"2020-08-18T00:56:26","slug":"sea-level-rise-drives-shoreline-retreat-in-hawaii","status":"publish","type":"post","link":"https:\/\/www.hawaii.edu\/news\/2013\/09\/10\/sea-level-rise-drives-shoreline-retreat-in-hawaii\/","title":{"rendered":"Sea-level rise drives shoreline retreat in Â鶹´«Ã½<\/span>"},"content":{"rendered":"Reading time: <\/span> 2<\/span> minutes<\/span><\/span>
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Example of chronic coastal erosion threatening a building on Maui. (Photo by Zoe Norcross-Nuu)<\/figcaption><\/figure>\n

Sea-level rise has been isolated as a principal cause of coastal erosion in Â鶹´«Ã½<\/span>. Differing rates of relative sea-level rise on the islands of Oʻahu<\/span> and Maui remain as the best explanation for the difference in island-wide shoreline trends (that is, beach erosion or accretion) after examining other influences on shoreline change including waves, sediment supply and littoral processes, and anthropogenic changes.<\/p>\n

Researchers from the University of Â鶹´«Ã½<\/span> at Mānoa’s School of Ocean and Earth Science and Technology (SOEST<\/abbr>)<\/a> and the state Department of Land and Natural Resources<\/a> recently published a paper showing that sea-level rise is a primary factor driving historical shoreline changes in Â鶹´«Ã½<\/span> and that historical rates of shoreline change are about two orders of magnitude greater than sea-level rise. “Are beach erosion rates and sea-level rise related in Â鶹´«Ã½<\/span>?” was published in Global and Planetary Change<\/em><\/a>. <\/p>\n

Knowing that sea-level rise is a primary cause of shoreline change on a regional scale allows managers and other coastal zone decision-makers to target sea-level rise impacts in their research programs and long-term planning. This study is confirmation that future sea-level rise is a major concern for decision-makers charged with managing beaches.<\/p>\n

“It is common knowledge among coastal scientists that sea-level rise leads to shoreline recession,” said Brad Romine<\/strong>, coastal geologist with the Sea Grant College Program<\/a>. “Shorelines find an equilibrium position that is a balance between sediment availability and rising ocean levels. On an individual beach with adequate sediment availability, beach processes may not reflect the impact of sea-level rise. With this research, we confirm the importance of sea-level rise as a primary driver of shoreline change on a regional to island-wide basis.”<\/p>\n

Globally averaged sea-level rose at about 2 mm per year over the past century. Previous studies indicate that the rate of rise is now approximately 3 mm per year and may accelerate over coming decades. The results of the recent publication show that sea-level rise is an important factor in historical shoreline change in Â鶹´«Ã½<\/span> and will be increasingly important with projected sea-level rise acceleration in this century. “Improved understanding of the influence of sea-level rise on historical shoreline trends will aid in forecasting beach changes with increasing sea-level rise,” said Charles Fletcher<\/strong>, associate dean and professor of geology and geophysics at SOEST<\/abbr>.<\/p>\n

Results of island-wide historical trends indicate that Maui beaches are significantly more erosional than beaches on Oʻahu<\/span>. On Maui, 78 percent of beaches eroded over the past century with an overall (island-wide) average shoreline change rate of 13 cm<\/abbr> of erosion per year, while 52 percent of Oʻahu<\/span> beaches eroded with an overall average shoreline change rate of 3 cm<\/abbr> of erosion per year.<\/p>\n

“The research being conducted by SOEST<\/abbr> provides us with an opportunity to anticipate sea-level rise effects on coastal areas, including Â鶹´«Ã½<\/span>’s world famous beaches, coastal communities and infrastructure. We hope this information will inform long-range planning decisions and allow for the development of sea-level rise adaptation plans,” said Sam Lemmo<\/a>, administrator, Department of Land and Natural Resources, Office of Conservation and Coastal Lands<\/a>.<\/p>\n

Read the UH<\/abbr> Mānoa news release<\/a> for more.<\/p>\n","protected":false},"excerpt":{"rendered":"

A study done by UH<\/abbr> Mānoa School of Ocean and Earth Science and Technology researchers find sea-level rise is a primary factor driving shoreline changes in Â鶹´«Ã½<\/span>. <\/p>\n","protected":false},"author":16,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[30],"tags":[801,378,92,9,438],"class_list":["post-19443","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-research","tag-coastal-erosion","tag-geology-and-geophysics","tag-school-of-ocean-and-earth-science-and-technology","tag-uh-manoa","tag-uh-sea-grant","entry","has-media"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t