Thousands of governors, mayors, CEOs and experts gathered Wednesday at a problem-solving summit to tackle global warming as a monster hurricane bearing the fingerprint of climate change threatens the US eastern seaboard.
While deadlocked UN-led talks sputter towards a December summit of national leaders, the three day conference spread across San Francisco will unveil scores of initiatives supporting the transition to a global economy fueled by clean energy rather than planet-warming fossil fuels.
Dozens of cities, provinces, states and multinational companies, for example, will pledge to run on clean energy -- mostly solar or wind -- within a few decades.
Leading the way, outgoing California governor Jerry Brown signed legislation Monday committing the state to purging greenhouse gases from its electricity grid by 2045.
"We all have the opportunity and the obligation to do our part to combat climate change," he told AFP after signing the bill into law.
Megacities will report greenhouse gas emissions trending downward, and nearly 1,000 institutional investors overseeing trillions in assets have, at least in part, turned their backs on planet-warming fossil fuels.
Pension funds in Europe, the United States and Japan announced shifts in their portfolios from brown to green energy.
Thirty-four governors from nine mostly tropical nations, meanwhile, unveiled partnerships supporting indigenous efforts to sustainably manage tropical, carbon-rich forests.
A consortium of nine philanthropies, including the Ford and Rockefeller Foundations, ponied up nearly half-a-billion dollars towards the same goal.
"This summit is going to be a showcase for the whole world in terms of climate action," said Ethan Elkind, head of the climate program at the Center for Law, Energy & the Environment at the University of California, Berkeley.
- 'Dark and dangerous future' -
Such efforts, however, have not been enough to salvage US commitments under the Paris climate treaty to reduce greenhouse gases, undermined by President Donald Trump's decision to scrap his predecessor's climate policies and promote the use of fossil fuels.
"Current federal and real economy commitments, combined with market forces, will drive US emissions to 17 percent below 2005 levels by 2025 -- roughly two-thirds of the way to the original US target," according to a report released Wednesday.
Under the Paris deal, the United States committed to cutting its carbon pollution 26-28 percent by 2025.
"The Obama target was always going to be a stretch," co-author Paul Bodnar, managing director of the Rocky Mountain Institute, told journalists.
"This work shows definitively that states, cities and businesses have the power to bring the nation to the brink of that ambitious target through their own authorities."
But the groundswell of climate action cannot obscure the fact that global warming continues to outpace efforts to tame it, in the US and across the globe.
After remaining stable for three years, raising hopes that they had peaked, carbon dioxide emissions from human sources rose in 2017 to historic levels.
"If we do not change course by 2020, we risk missing the point where we can avoid runaway climate change," UN Secretary-General Antonio Guterres said earlier this week, warning of a "dark and dangerous future."
The 196-nation Paris Agreement calls for capping global warming at "well below" two degrees Celsius (3.6 degrees Fahrenheit), and vows to strive for a 1.5 C limit if possible.
- 'We Are Still In' -
But even if all nations honor voluntary carbon-cutting vows submitted in an annex, we are trending toward a world at least 3 C warmer than the preindustrial era, a scenario scientists say would tug at the fabric of civilization.
"Earth hasn't seen 3 C in three million years," said Lord Nicholas Stern, the first economist to seriously calculate the costs and benefits of taking action to halt climate change.
"With only one degree Celsius of warming so far, we are experiencing very severe effect," including deadly heatwaves, flooding, and storm surges engorged by rising seas, he told AFP.
Taking bold action now, he added, could deliver trillions of dollars in benefits, ranging from avoided costs to millions of jobs in low-carbon economies.
Trump opted out of the Paris Agreement shortly after gaining office, and has hammered away at the domestic and international climate policies of his predecessor, Barack Obama.
His administration has sought to relax pollution rules for coal-fired power plants and roll back car-mileage standards, the twin pillars of Obama's Clean Energy Plan.
US mayors, governors and business leaders -- under the banner "We Are Still In" -- have pushed back by adopting more ambitious targets at the local level.
Taken together, these jurisdictions represent about half of the US economy, the equivalent of the third-largest country in the world, according to the report.