SECTION 1. Section 1 of chapter 21N of the General Laws, as appearing in the 2020 Official Edition, is hereby amended by striking out the definition of “Carbon dioxide equivalent” in lines 17 to 21, inclusive, and inserting in place thereof the following definition:-

“Carbon dioxide equivalent”, the amount of carbon dioxide by weight that would produce the same global warming impact as a given weight of another greenhouse gas calculated for a timeframe of 20 years and for a timeframe of 100 years, based on the best available science, including from the Intergovernmental Panel on Climate Change.

SECTION 2. Said section 1 of said chapter 21N, as so appearing, is hereby further amended by striking out the definition of “Statewide greenhouse gas emissions” in lines 92 to 99, inclusive, and inserting in place thereof the following definition:-

“Statewide greenhouse gas emissions”, the total annual emissions of greenhouse gasses in the commonwealth, including all emissions of greenhouse gasses from the generation of electricity and the distribution and use of gas delivered to and consumed in the commonwealth, accounting for electric transmission and distribution line losses, and accounting for losses of gas in the commonwealth in transmission, storage, distribution, and use by consumers, whether the electricity is generated or the gas is produced in the commonwealth or imported; provided, however, that statewide greenhouse gas emissions shall be expressed in tons of carbon dioxide equivalents and reported for a timeframe of 20 years and a timeframe of 100 years.

SECTION 3. Section 2 of said chapter 21N is hereby amended by striking out subsection (b) and inserting in place thereof the following:-

(b) The department shall: (1) consult with the secretary on periodic review and updates of emission reporting requirements, as necessary; (2) review existing and proposed state, federal and international greenhouse gas emissions reporting programs and make reasonable efforts to promote consistency among the programs established pursuant to this chapter and other programs and to streamline reporting requirements on greenhouse gas emissions sources; and (3) every 3 years use the best available science, including from the Intergovernmental Panel on Climate Change, to review and update carbon dioxide equivalents and factors that impact statewide greenhouse gas emissions, and, retroactive to 1990, adjust the accounting of statewide greenhouse gas emissions; provided further, that if the results of such update are not consistent with federal reporting requirements, the department may issue 2 reports.