PORTLAND — In a state where salmon runs are obsessively monitored, snowpack levels are of statewide interest, politicians trip over themselves to woo renewable energy companies and the coastline belongs to the public, Oregonians are often presumed to be among the nation’s most environmentally aware voters.

So it follows that Arizona Sen. John McCain, the Republican presidential contender, chose to unveil a sweeping new plan for combating global warming in Portland Monday, during his first trip to the state of the 2008 election cycle.

But will McCain’s global warming pitch work with green-savvy voters, not just in Oregon, but places like Washington and California, traditional Democratic strongholds where McCain’s advisers have said he believes he can compete for votes from independents and moderate Democrats?

Maybe, is the answer, particularly for voters who will be impressed that a Republican is addressing the climate change issue head-on, a marked departure from the Bush administration.

Bob Doppelt, director of the climate leadership initiative at the University of Oregon, said speeches like McCain’s — in which he called for a mandatory limit on greenhouse gas emissions — can help move the global warming issue beyond the “is it real?” debate that has dogged the topic.

“It makes it very clear that this is a problem that we must deal with,” Doppelt said. “John McCain has helped put that issue out there, front and center. There will be lots of room to debate the specifics of what the best policy is.”

Jane Lubchenco, a marine biology professor at Oregon State who has advised Democratic Gov. Ted Kulongoski on global warming issues also called McCain’s stance was a welcome change for the GOP.

“In view of the strong scientific evidence about climate change and its impacts, it is quite refreshing to see the presumptive Republican candidate take a strong stand on concrete ways to reduce greenhouse gas emissions,” she said.

But some environmental activists, who maintain large voter databases and can count on an active volunteer corps during election-time, said McCain’s plan skimped on key details.

“It’s nice that he is talking about combating climate change, but it’s not enough,” said Jonathan Poisner, executive director of the Oregon League of Conservation Voters. “The plan that he has put forward is significantly less than the U.N. intergovernmental panel on climate change says is necessary if we are to stop rising carbon emissions.”

And Poisner pointed out that while McCain called for trimming emissions 60 percent below 1990 levels by 2050, Democrats Hillary Clinton and Barack Obama have said they should be cut by 80 percent by mid-century.

Sallie Schullinger-Krause, program director for global warming at the Oregon Environmental Council, said McCain’s stance on nuclear power — that it was a viable trade-off for cutting coal use and emissions — left unanswered serious questions on waste disposal.