Hawaii Greenhouse Gas Program

New Release:  Hawaii Greenhouse Gas Emissions Report for 2005, 2018, and 2019, Final Report (dated April 2023)


The Department of Health has established the Hawaii Greenhouse Gas (GHG) Program to combat the threat of climate change and sea level rise.  The program utilizes the Air Pollution Control Permit process of the Clean Air Branch to regulate GHG emissions statewide.  The Hawaii GHG program works in conjunction with other Federal and Hawaii State programs to mitigate GHGs.


Act 234 of the 2007 Legislature established the foundation for the Hawaii GHG Program.  It declared a policy to reduce GHG emissions statewide to 1990 levels by 2020.  Act 15 of the 2018 Legislature established a statewide carbon net-negative goal by 2045.  Act 238 of the 2022 Legislature established a goal for the level of statewide GHG emissions to be at least 50 percent below 2005 levels by the year 2030 (including airplane emissions).

On June 30, 2014, Hawaii Administrative Rules (HAR), Chapter 11-60.1 was amended to adopt the new Hawaii GHG program.  The main requirements of the program are set forth in Subchapter 11, Greenhouse Gas Emissions. During promulgation, public comments were solicited and received and a response to comments was provided.

Large Existing Covered Sources

To reduce GHGs, the rules specify a 16% GHG emission cap for large existing stationary sources (“affected sources”) with potential carbon dioxide equivalent (CO2e) emissions at or above 100,000 tons per year.  Each affected source must submit a GHG emission reduction plan for establishing measures that will be used to meet the emission cap.  The approved GHG emission cap and associated monitoring, recordkeeping, and reporting provisions will be made part of the facility’s covered source permit.  The deadline for submitting GHG emission reduction plans was June 30, 2015.  The Clean Air Branch has received GHG emission reduction plans from all affected facilities for incorporating GHG emission caps into the air permits pursuant to HAR §11-60.1-204(d)(6)(C).

See the Instructions for GHG Emission Reduction Plan (PDF).

Greenhouse Gas Emission Inventories

HAR §11-60.1-204(k) requires the Department of Health to provide reports with updated GHG emissions inventories showing progress towards achieving statewide GHG reduction goals.

Emission inventory reports for Hawaii showing statewide CO2 Eq emissions and sinks (GHG removals) are provided in the links below.  The most recent 2005, 2018, and 2019 report dated April 2023 was prepared by ICF and the University of Hawaii Economic Research Organization (UHERO) for the Department of Health.  The GHG emission inventories serve as a basis for decision making and provide direction in future GHG reduction efforts.

As of 2019, the Act 234 statewide GHG emission limit of 15.38 million metric tons (MMT) CO2 Eq has been reached, and statewide GHG projections of 11.58 MMT, 9.38 MMT, and 5.36 MMT for 2020, 2030, and 2045 respectively, indicate Hawaii is on target to meet its statewide GHG emissions limit by 2020 and will continue to meet the limit after 2020.  Act 15 (net negative by 2045 goal) and Act 238 (50% below 2005 GHG levels by 2030 goal) emission targets are not projected to be met by their goal years.  These findings will be reassessed and updated in the forthcoming emissions report for 2020 and 2021.


If you have any questions, please contact Mr. Scott Takamoto or Mr. Mike Madsen of the Clean Air Branch at (808) 586-4200.

All Covered Sources

Beginning in 2015, GHG emissions must be included in the calculations to determine annual fees for all facilities holding a covered source permit. Utilize GHG emissions factors and global warming potentials to calculate your CO2e emissions for covered source permit fees.

Related Topics

Please click on the following links to learn more about related topics:

Other Hawaii State agencies have initiated a number of programs to reduce GHGs, including the following:

Hawaii Revised Statutes – some key sections pertaining to Greenhouse Gas include the following: