Rising Sea Level

  • Ongoing Local Sea Level Rise. The Honolulu tide gauge has measured a rise in sea level of nearly ½ foot since 1905.
  • Beach Erosion from Sea Level Rise is already happening. Over 70% of beaches in Hawai‘i are in a state of chronic erosion, likely caused by a combination of shoreline hardening and ongoing sea level rise.
  • More frequent high tide flooding. The frequency of high tide flooding in Honolulu since the 1960s, has increased from 6 days per year to 11 per year. High tide flooding is produced by wave over-wash and reverse flow through storm drains into basements and onto streets—you don’t have to live on the coast to see this kind of flooding.
  • Hawaiian cultural practices are affected. In Hawaiʻi, sea level rise impacts on traditional and customary practices (including fishpond maintenance, cultivation of salt, and gathering from the nearshore fisheries) have been observed. Because of flooding and sea level rise, indigenous practitioners have had limited access to the land where salt is traditionally cultivated and harvested since 2014. Detachment from traditional lands has a negative effect on people’s spiritual and mental health.
  • What’s coming? About 550 cultural sites, 38 miles of major roads, and more than $19 billion in assets will be vulnerable to chronic flooding resulting from a 3.2 ft increase in sea level. Such widespread flooding will change the character of the island by affecting cultural heritage and daily commerce/lifestyles.