(1) The requirements of the greenhouse gas emissions reduction subelement of the climate change and resiliency element set forth in RCW 36.70A.070 apply only to those counties that are required or that choose to plan under RCW 36.70A.040 and that also meet either of the criteria set forth in (a), (b), or (c) of this subsection on or after April 1, 2021, and the cities with populations greater than 6,000 as of April 1, 2021, within those counties:

(a) A county with a population density of at least 100 people per square mile and a population of at least 200,000;

(b) A county bordering on the Columbia and Snake rivers with a population density of at least 75 people per square mile and an annual growth rate of at least 1.65 percent; or

(c) A county located to the west of the crest of the Cascade mountains with a population of at least 130,000.

(2) The requirements of the amendments to the transportation element of RCW 36.70A.070 set forth in chapter 228, Laws of 2023 apply only to: (a) Counties and cities that meet the population criteria set forth in subsection (1) of this section; and (b) cities with populations of 6,000 or greater as of April 1, 2021, that are located in a county that is required or that chooses to plan under RCW 36.70A.040.

(3) The requirements of the amendments to the land use element of RCW 36.70A.070 set forth in chapter 228, Laws of 2023 apply only to: (a) Counties and cities that meet the population criteria set forth in subsection (1) or (2) of this section; and (b) counties that have a population of 20,000 or greater as of April 1, 2021, and that are required or that choose to plan under RCW 36.70A.040.

(4) Once a county meets either of the sets of criteria set forth in subsection (1) of this section, the requirement to conform with the greenhouse gas emissions reduction subelement of the climate change and resiliency element set forth in RCW 36.70A.070 remains in effect, even if the county no longer meets one of these sets of criteria.

(5) If the population of a county that previously had not been required to conform with the greenhouse gas emissions reduction subelement of the climate change and resiliency element set forth in RCW 36.70A.070 changes sufficiently to meet either of the sets of criteria set forth in subsection (1) of this section, the county, and the cities with populations greater than 6,000 as of April 1, 2021, within that county, shall adopt a greenhouse gas emissions reduction subelement of the climate change and resiliency element set forth in RCW 36.70A.070 at the next scheduled update of the comprehensive plan as set forth in RCW 36.70A.130.

(6) The population criteria used in this section must be based on population data as determined by the office of financial management.