OLYMPIA — Washington House Democrats passed a bill Sunday declaring climate change an “existential threat” and mandating a carbon-neutral state by 2050.

Also on Sunday, the House approved legislation to require some counties and cities to adopt land-use rules that would help the state achieve its carbon limits.

Both bills go to the Democratic-controlled Senate, where similar measures were introduced this session but failed to meet deadlines to be approved by committees.

House Bill 2311 would require Washington to cut carbon emissions to 45% below 1990 levels by 2030 and by 95% by 2050. Projects to store carbon would offset the remaining 5%, according to the bill. The legislation does not lay out a carbon-reduction plan, or outline penalties for exceeding the limits.

The bill would revise standards originally set in 2007 that called for the state to cut emissions by 25% by 2035 and 50% by 2050. Proponents of the bill say limits need to be readjusted to keep average temperatures from rising by 2.7 degrees Fahrenheit above pre-industrial levels.

The bill passed on largely a party-line vote, 55-41, with no Republican voting yes. House Agriculture and Natural Resources Committee Chairman Brian Blake of Aberdeen was the only Democrat to vote no.

The revised limits would put Washington more in line with its West Coast neighbors. Oregon’s goal is to cut carbon emissions by 75% below 1990 levels by 2050. California’s goal is to cut carbon emissions by 80% by 2050, but become carbon neutral by 2045.

House Bill 2427 adds combating climate change to the goals of the state’s Growth Management Act. The bill directs eight larger counties and the cities in those counties to use planning laws to reduce carbon emissions. The bill encourages other counties and cities to plan for climate change.

The bill originally applied to all counties. The bill also was amended to commission a study by Washington State University and the University of Washington on the effect on salmon of “urban heat islands.”

The amended bill won some Republican votes and passed 59-37.