SAN FRANCISCO — With President Donald Trump mute and Congress moribund on the issue of climate change, it feels to many like official Washington is fiddling while the world burns. That sense became literal this summer, as wildfires charred broad swaths of the drought-stricken West for a second straight year.

California Gov. Jerry Brown will seize the initiative on the issue this week by hosting a global climate conference here that seeks to shift attention away from the stymied national government to regional governments, businesses and individuals worldwide that are pledging to do more to rein in global warming.

Brown on Monday signed two ambitious measures that enhance California’s claim to international leadership on the issue. Many more pledges are planned for the days ahead at the Global Climate Action Summit — on everything from preserving and expanding oxygen-producing forests, to fast-tracking the use of electric vehicles, to cracking the conundrum of how to store power produced by “intermittent” fuels like wind and solar.

Gov. Jerry Brown, untethered from any re-election concerns, will take center stage in the fight against climate change and Trump administration environmental policies as he hosts a global climate summit in San Francisco that begins Wednesday. Rich Pedroncelli / AP

But the pledges from California and others will mean little, analysts here said, without even greater movement — and participation from all of the world’s 195 national governments — away from the fossil fuels that still generate much of the world’s electricity and power most of its cars and trucks.

“Both the nonstate actors and nations can be more ambitious,” said Angel Hsu, who led recent research by Data-Driven Yale, which teamed with other scientists to analyze the climate plans of nearly 6,000 cities, states and regions, and more than 2,000 companies, worldwide. “We are not there yet. There needs to be more.”

With myriad pledges in the air, the study suggests that much depends on promises being kept. Full implementation of the reported city, region and company commitments would get the U.S. halfway to the commitment it made under the 2015 Paris climate accord: to reduce greenhouse gas emissions 26 to 28 percent below 2005 levels by 2025, Hsu’s research concluded.

Even more ambitious commitments by multi-national nonprofits and corporations could help spur the U.S. to meet or even exceed the Paris benchmark, the research found, even though President Donald Trump withdrew the U.S. government from the agreement more than a year ago. (One such global effort comes from the group RE100 — to get 100 big businesses to obtain 100 percent of their electricity from green sources.)

The plethora of pledges, even unfulfilled, amount to the good news. The bad news is that even if every nation on Earth met the benchmark pollution goal set in Paris, the result would still be a 3 degrees Celsius hike in global temperatures, compared to pre-industrial levels, according to the Yale research. Scientists agree that any increase of more than 2 degrees would plunge Earth into the danger zone.

Those findings have not been lost on Brown. “The emissions keep mounting. Global warming is not stopping,” Brown said in an interview with NBC News this week. “So we have got to do a lot more. And this summit is a way to boost ambition and push the parties to do better.”

Players and promises

The summit will draw an estimated 5,000 people, including former Vice President Al Gore; former Secretary of State John Kerry; China’s top climate minister, Xie Zhenhua; Starbucks CEO Kevin Johnson; musician Dave Matthews; and actor Alec Baldwin.

The ultimate goal of the climate activists is for the world to reach “carbon neutrality” by midcentury. That would mean reducing greenhouse gases enough so they can be safely absorbed by forests, oceans, soil and other natural systems. When the conference wraps up Friday, participants are set to release a sharply worded “call to action” for the U.S. and other national governments to aim more intently at that goal.

While governments will be crucial to any successful bid to defeat the profusion of heat-trapping gases, Brown and the planners of the Global Climate Action summit know that they can also be fickle. Witness Canada’s whipsaw from Stephen Harper’s regime, packed with climate change skeptics, to Justin Trudeau’s greenhouse-gas-fighting administration. America lurched in the opposite direction: replacing Barack Obama and his campaign for the Paris agreement, with Donald Trump’s fossil-fuel-friendly White House.

The San Francisco gathering envisions a kind of “bottom up” climate action that will become so deeply embedded in the world’s economy and culture that it can’t be reversed, even by national leaders.

In just a little more than a year, the U.S. already has added enough new electrical capacity for solar, wind and other renewable sources to power more than 3 million homes a year. The country has drawn up mass transit plans that should cut a total of 36 billion miles of car and truck travel by 2025.

And progress on other fronts is well within reach, according to America’s Pledge, the organization formed by Brown and former New York Mayor Michael Bloomberg to make good on America’s previous international climate commitments.

America’s Pledge called in a report Wednesday for bold action on 10 fronts by 2025. Among the proposed goals: shuttering plants responsible for producing 30 percent of America’s coal-fired power, doubling the number of electric vehicles on the road, to 8.4 million, and fully activating carbon trading markets in at least 16 states, to goad a faster flight away from fossil fuels.

The U.S. has already cut its carbon output by about 14 percent from 2005 to 2016. And with enactment of the 10 measures outlined by America’s Pledge, the U.S. could bring the load down to 21 percent below the 2005 mark — within sight of the Paris goal, according to the group’s analysis.

In the days and weeks leading into Wednesday’s summit kickoff, other organizations rolled out initiatives they said demonstrated the power of sub-national action:

Nine of the world’s biggest nonprofits and foundations — including the Ford Foundation and the David and Lucile Packard Foundation — announced they would spend at least $459 million through 2022 to protect, restore and expand the world’s forests and open spaces. Such “land-based” initiatives have the potential for absorbing carbon and delivering up to 30 percent of the carbon dioxide reductions envisioned in the Paris agreement, the coalition said.

Nineteen major cities — including New York, Los Angeles, Toronto, Tokyo, Sydney, Paris and London — committed that, by 2030, new buildings would add a net of no new greenhouse gases to the atmosphere. Heating, air-conditioning and other building systems account for more than half of carbon dioxide emissions in cities, the alliance said.

A total of 476 major companies globally — including tech giants Adobe Systems and Dell Technologies — have signed on to abide by stringent carbon limits and to have those guidelines verified by outside analysts. The Science Based Targets coalition argues that adopting new technologies and cutting pollution will boost the world’s economy.

Trump's presence without attendance

Trump and his advisers appear nowhere on an agenda of more than 350 workshops, seminars and demonstrations. But they have spoken loudly in their absence.

In addition to the June 2017 withdrawal from the Paris agreement, Trump’s Environmental Protection Agency has fought tenaciously to lend support to a coal industry in retreat because of competition from cheaper wind, solar and natural gas. Last month, Trump rolled back tougher mileage standards for cars and moved to take away California’s power to maintain more ambitious mileage goals. And, this week, the administration revealed plans to make it easier for energy companies to release heat-trapping methane during their drilling operations.