“I was elected to represent the citizens of Pittsburgh, not Paris,” U.S. President Donald Trump said, announcing his decision to pull America out of the Paris climate agreement.

Mr. Trump sought to make Pittsburgh the metaphor of his ‘America First’ politics. As it turned out, it is not only his brand of nationalist politics that this statement spurred, Pittsburgh has also come to symbolise climate globalism in the last few days.

Since Mr. Trump’s statement, Pittsburgh, a city of more than three lakh, 400 km northwest of Washington and 600 km west of New York City, has become the metaphor of a future beyond fossil fuels.

What is the plan?

“Last week, President Donald Trump tried to pit our two cities against each other when he announced the pull-out of the Paris Agreement on Climate Change. As the Mayors of Pittsburgh and Paris, we’re here to say that we’re more united than ever,” Mayor of Paris Anne Hidalgo and Mayor of Pittsburgh William Peduto wrote in a joint op-ed in The New York Times this week.

Pittsburgh is today at the frontier of futuristic technology but its history is also a guide. It is the history of American capitalism.

The Pennsylvanian city sits in the midst of vast reserves of coal. Andrew Carnegie, one of the builders of modern America, was born to Scottish parents here and grew up to pioneer mass steel production. Carnegie left a complex legacy of entrepreneurism, philanthropy, labour oppression and greed — all features that would define American capitalism in the 19th and early 20th century. And environmental degradation. As Pittsburgh steel mills fired by coal dug from mines all around ramped up production to meet the surge in demand during the Second World War, the city was enveloped by a smog. Streetlights stayed on round the clock in the 1940s.

Then came globalisation and Chinese steel. One after another, steel mills and mines around the city closed. The last steel mills closed in 1999. Abandoned mines and shuttered plants fired Mr. Trump’s politics.

How has it reinvented itself?

But the city of Pittsburgh overcame the shock of globalisation fast, though that cannot be said of the coal country that surrounds it. Carnegie Mellon University (CMU) began developing autonomous driving vehicles three decades ago, and the city today hosts research facilities of all digital giants — Apple, Google and Facebook, among the more than 1,600 of them. This is the first city that Uber has chosen to trial-run its ‘driver-less cars.’

Around CMU and numerous other universities, a futuristic ecosystem is taking shape in the city. It hopes to shift to 100% renewable energy by 2035, and has 13,000 people employed in renewable technology research.

Why is it going against Trump?

Mr. Trump’s statement brought international focus on Pittsburgh and Mayor Peduto became the face of resistance to the official U.S. policy of climate denial. “For decades, Pittsburgh has been rebuilding its economy based on hopes for our people and our future, not on outdated fantasies about our past. The City and its many partners will continue to do the same, despite the President’s imprudent announcement,” he said the day after Mr. Trump’s announcement. “As the Mayor of Pittsburgh, I can assure you that we will follow the guidelines of the Paris agreement for our people, our economy and future,” he said, prompting a national mobilisation, endorsed by former President Barack Obama, of 250 U.S. cities and several States that have now made similar commitments.

Why is it polarised?

But the future that Pittsburgh holds out could also be deeply polarising. More than three quarters of Pittsburgh voters chose Hillary Clinton, Mr. Trump’s opponent, in last year’s election. But in the surrounding counties in rural Pennsylvania, untouched by the future and ravaged in the present, Mr. Trump triumphed, becoming the first Republican to win the State of Pennsylvania since 1988, which was a major factor in his national victory.