Portland voters could get the chance this fall to weigh in on a proposed tax on sales at powerhouse national retailers operating inside city limits. The surcharge is intended to fund initiatives to put a dent in global climate change.

The city attorney released an official ballot title for a proposed measure Friday. If proponents gather enough signatures, the campaign would pit a broad coalition of liberals and environmentalists against the corporations that would be affected by the tax.

The petition would amend city code to apply a 1 percent tax to all Portland sales by large corporations except medicine, health care and certain groceries. Companies would be affected if they have at least $1 billion in annual sales and sales of $500,000 within Portland city limits. It's not clear how much money the surcharge would raise.

Revenue generated by the tax would be deposited in a fund earmarked for renewable energy projects, environmentally friendly construction and green sector job training targeted at people of color, women, the disabled and chronically unemployed.

The petition's backers are organized via a group called the Portland Just Energy Transition Initiative, which boasts dozens of local member organizations involved in climate and civil rights advocacy. The group is being assisted on a volunteer basis by veteran Democratic campaign operative Paige Richardson, who managed former Gov. Ted Kulongoski's re-election efforts. Richardson also headed the campaign to put special labels on genetically modified foods sold in Oregon that failed by the narrowest of margins in 2014.

E.D. Mondaine, one of the measure's two chief petitioners, said in a statement that the proposal is meant to help the city reach its greenhouse gas emissions goals "while ensuring there is an equitable and just distribution of resources so that all Portlanders benefit." Mondaine, a pastor active with the local NAACP, said his measure can "create a consistent funding stream" for environmentally-friendly projects that specifically assist Portlanders in poorer neighborhoods.

The Portland Business Alliance has already lined up to oppose the proposed ballot measure. In a statement, the group said the tax "will ultimately be passed on to consumers and small businesses." The group also said the tax does not address Portland's most pressing issues: homelessness, traffic jams and a lack of affordable housing.

If their petition qualifies for the ballot, the green energy coalition will likely have to build a war chest to compete against a number of business and retail giants that will oppose their measure. Last time a similar, but statewide, tax was on the ballot – Measure 97, in 2016 – corporate interests raised nearly $28 million and soundly defeated the tax by framing it as bad for consumers. Even with that level of spending by opponents, however, Measure 97 passed 57 percent to 43 percent in Multnomah County, and city of Portland voters historically have been more pro-tax than county voters as a whole.

Friday's release of the ballot title kicks off a seven-day period during which any registered voter living in Portland can challenge the title in Multnomah County Circuit Court. After any challenge is resolved, backers of the proposal have until early July to gather the 34,156 valid signatures needed to put the petition on the November 2018 ballot, said Deborah Scroggin, Portland's top elections official. The petitioners have filed paperwork showing they intend to hire paid signature gatherers, she said.

Several things can happen if backers gather enough signatures: City councilors could adopt the petition outright, sponsor their own competing measure or let the voter-sponsored petition head to the ballot.

While city officials sometimes refer measures to Portland ballots, it is rarer for a citizen-sponsored petition to go before voters. The last times that happened was in 2013, when city voters overwhelmingly rejected Measure 26-151, a proposal to fluoridate Portland's drinking water, and in 2014, when city voters also turned down a citizen-sponsored measure that would have wrested control of the city's water and sewer system and given it to an independent board.

-- Gordon R. Friedman

503-221-8209; @GordonRFriedman