Hawaii's Changing Climate: Legislative Briefing Sheet 2010

Jessi Kershner
Posted on: 12/22/2010 - Updated on: 3/02/2020

Posted by

Jessi Kershner

Project Summary

The effects of global climate change are already being felt in Hawaii and are likely to continue, resulting in growing impacts to the natural resources that people depend on. Because the State of Hawaii is still in the initial phases of understanding and planning for climate change, the Center for Island Climate Adaptation and Policy (ICAP) partnered with Dr. Chip Fletcher at the University of Hawaii to produce a legislative briefing sheet designed to communicate scientific understanding of how climate change will affect Hawaii. This briefing sheet was intended to lay the groundwork for climate change-related legislation in the state.


Hawaii’s climate is already changing in ways that are consistent with global climate change: air temperature has risen; rain intensity has increased while total rainfall has decreased; stream flows have decreased; sea level and sea surface temperatures have increased; and the ocean is becoming more acidic. These trends are likely to continue, and will result in growing impacts to Hawaii’s water resources, forests, coastal communities, and the marine ecosystem.

In 2009, ICAP partnered with Dr. Chip Fletcher at the University of Hawaii to produce Hawaii’s Changing Climate Briefing Sheet, 2010. Dr. Fletcher leads the Coastal Geology Group at the UH School of Ocean and Earth Science and Technology and specializes in coastal hazards (e.g., sea level rise) and shoreline evolution. The purpose of the briefing sheet was to communicate scientific understanding and knowledge, as published in peer-reviewed scientific journals and government reports and websites, of how climate change is affecting, and will affect Hawaii in the future. The briefing sheet was directed at state and county legislators, as well as government agencies.


Planning for climate change impacts is still in its infancy in the State of Hawaii, which is thought to be due to a lack of accessible information on potential climate changes and what features are most at risk from these changes. In order to address this knowledge gap, Dr. Chip Fletcher translated peer-reviewed literature and government reports and websites into one document summarizing past, current, and predicted changes in Hawaii’s climate. Specifically, Dr. Fletcher examined potential changes in surface air temperature, rainfall and stream discharge, rain intensity and other potential water cycle impacts, sea level, sea surface temperature, and ocean acidification. Identified changes and potential impacts include:

  • Air temperature has risen in the past 30 years (approximately 0.3°F per decade), with stronger warming at elevations above 2600 feet. The greater warming trend at high elevations threatens water resources and native forests.
  • Total rainfall has steadily declined about 15% over the past 20 years while the amount of rain falling in the heaviest downpours has increased approximately 12%, which could trigger flash flooding, mudslides and debris flows, road and business closure, infrastructure damage, and loss of public services in isolated communities.
  • Stream base flow has declined in Hawaii since the early 1940s, and the cause is likely related to decreased rainfall. Rising air temperatures, decreased rainfall, and decreased steam flow threatens unique ecosystems that support diverse plants and animals, as well as Taro farming (a form of wetland agriculture).
  • Sea level has risen over the past century (approximately 0.6 inches per decade). Sea level rise accelerates and expands erosion, potentially impacting beaches that were previously stable and accelerating chronic beach erosion. Continued sea level rise may also increase marine inundation of coastal roads and communities, intensify salt intrusion in coastal wetlands, groundwater systems, and estuaries, and intensify drainage problems leading to increased flooding.
  • Sea surface temperatures have increased approximately 0.22°F per decade and this rate is likely to rise, potentially leading to more incidences of coral bleaching.
  • The surface ocean around Hawaii has grown more acidic as carbon dioxide in the atmosphere has increased, which can lead to a host of negative impacts on marine organisms such as corals, plankton, algae, and shellfish.

Outcomes and Conclusions

Because these trends are likely to continue into the future, it is important to begin considering mitigation and adaptation strategies now. Scientists recommend sustained and enhanced climate monitoring and assessment activities, as well as focused research that will produce models of future climate changes and impacts. To lay the groundwork for moving climate change-related legislation forward in the state, the briefing sheet was sent to every legislator (state and county) and agency in the State of Hawaii. 


Kershner, J. (2010). Hawaii's Changing Climate: Legislative Briefing Sheet 2010 [Case study on a project of the University of Hawaii and Center for Island Climate Adaptation and Policy]. Product of EcoAdapt's State of Adaptation Program. Retrieved from CAKE: http://www.cakex.org/case-studies/hawaiis-changing-climate-legislative-… (Last updated December 2010)

Project Contacts

Affiliated Organizations

The Center for Island Climate Adaptation and Policy (ICAP) facilitates a sustainable, climate-conscious future for Hawaiʻi, the Pacific, and global island communities.  ICAP produces innovative, interdisciplinary research and solutions to island decision-makers in the public and private sectors.  As a focal point for University of Hawaiʻi (UH) climate expertise, ICAP serves as a two-way conduit between the university and island communities to catalyze climate change adaptation and resiliency.

An Interdisciplinary Endeavor