By Laurie Goering
NEW YORK, Sept 20 (Thomson Reuters Foundation) - Ben Davis'father spent his career working at a petroleum company. But onFriday, Davis - a chemical engineer, like his dad - didsomething he'd never done before.
He joined Swedish teenage activist Greta Thunberg in aprotest to demand action on climate threats.
"We've run out of time for gradual change," said the38-year-old university teacher, who took the day off work toanswer a call by student climate protesters for adults to jointhem for the first time Friday in a global strike.
"I understand the magnitude of the problem. For me thescience is not confusing or ambiguous. We need drastic change,"he said. "That I'm out here should trouble a lot of people."
Friday's marches, in cities from New York to London andJohannesburg to New Delhi, had been expected to be the largestclimate change protests yet, spurred partly by adding adults tothe past year's mainly youth-led mobilizations.
Global climate campaign group 350.org said late Fridayafternoon that organizers estimated more than 4 million peoplehad taken to the streets. About 3,000 companies closed theirdoors in support of the climate strikes, it said.
The protests, in advance of a U.N. summit Monday aimed ataccelerating action to tackle global warming, kicked off a weekin which more than 5,800 climate change-related strikes andother events are set to take place in 163 countries, 350.orgsaid in a statement.
New York City officials estimated that 60,000 people marchedthere. Steel workers, nurses and other unionized employeesjoined the Manhattan protest, already swelled after cityauthorities let children miss school without penalty Friday.
Many of the adults on the streets of New York said it wasthe first time they had picked up a protest sign over climatethreats.
Justin Flood, 37, a graphic designer, said the globaladvertising agency he works for had shut its doors entirelyFriday to let its staff join the rally.
"I feel like protest is the only way to have an outlet forthe anxiety around this issue," said Flood, who carried a signreading, "Sorry we're closed due to climate crisis".
With the planet's climate showing signs of reachingdangerous tipping points, but politicians failing to act onthem, "what else are we going to do?" he asked.
Around him, marchers - the majority of them students -chanted and waved banners with messages ranging from "Don't Be aFossil Fool" to "Act Now or Swim Later".
'RED FLAG'
Richard Evans, 61, joined the New York rally after travelingthree and a half hours from his home in rural Pennsylvania withhis wife, a teacher.
They hefted a homemade banner made from an old sheet: "Facereality now, for our children".
Evans, an ecologist who works for the U.S. national parkservice, said he'd helped switch the park he works at entirelyto wind power.
He had once had faith a transition to clean energy - acrucial part of limiting climate change - was well underway inthe United States.
"I tried to be patient, but when things started goingbackward, I lost my patience," he said, referring to moves byPresident Donald Trump's administration to promote fossil fuels.
"I can understand slow progress, but not going backward anddisrespecting science," he said.
Evans said he had never protested before and hated crowds,adding it was "contrary to my whole personality to be out here".
But writing to politicians had not worked, he said.
"People say these protests don't do anything. But they are ared flag that if nothing happens this (movement) is going to getbigger," he said.
Alethea Shapiro, 40, had another reason for joining theprotests with her four children: She'd seen the destruction ofHurricane Sandy in 2012 firsthand, when a huge tree fell on partof their house in Long Island.
"In the last year the natural disasters have really pickedup, from fires to hurricanes," she said. But "there's still adisconnect. People should be paying attention but they're not."
Kacy Wiggins, 50, who skipped work as a math lecturer toattend the rally with his 12-year-old daughter, said he fearedthe protests would have little immediate effect.
"Real change won't come until these students are old enoughto vote," he predicted. But the protests "are an omen" ofpolitical change coming, he said.
Sukhman Dhami, 41, a human rights lawyer and anotherfirst-time climate protester, however, saw the strikes as acrucial step in spurring the measures needed to reduce climaterisks.
"Scientists establish the facts but it's up to communitiesand people to demand everyone act on this," he said, predictingthe protest movement "absolutely" would begin to shift policyover time.
"Greta Thunberg has inspired millions of Gretas - young andold," he said.(Reporting by Laurie Goering @lauriegoering; editing by MeganRowling. Please credit the Thomson Reuters Foundation, thecharitable arm of Thomson Reuters, that covers humanitariannews, climate change, resilience, women's rights, traffickingand property rights. Visit http://news.trust.org/climate)