Creating a safe and livable future for humanity would appear to be an obvious goal for all. Yet, in 2025, the climate movement has never faced a more hostile and coordinated opposition.
Within the new U.S administration—and a growing number of political parties across the world—we now have climate deniers openly working to dismantle years of painstaking climate diplomacy and action. This creates huge risks for us all.
We are already seeing the stark consequences of the failure of nation states to do enough. Wildfires, hurricanes, rising sea levels and extreme heat are all becoming more frequent and severe. Carbon dioxide levels in our atmosphere are now over 420 parts per million—20 percent higher than when the UN climate negotiations began nearly three decades ago.
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But as we mark the 55th anniversary of Earth Day, under the banner of “Our Power, Our Planet,” we can draw hope from the difference that cities, communities and individuals can still make to tackle the climate crisis. Cities are proving that a greener and healthier way of life is not only possible, but already delivering tangible benefits—from well-paid green jobs to less polluted neighborhoods.
The first Earth Day in 1970 sparked a movement in the United States that led to the Clean Air Act, the Clean Water Act and the creation of the Environmental Protection Agency. Today, the U.S. may be run by those who seem willing to squander the economic opportunities of the green economy, but cities around the world are already seizing them.
From London to Los Angeles, and São Paulo to Seoul, cities are powering a formidable climate movement that is having a real impact. London has put in place the world’s largest clean air zone, helping to bring down emissions and dramatically clean up its air. The city has also brought forward its net zero target to 2030, which is helping to accelerate green investment, boost business and grow the low-carbon economy. London knows it would be foolish to miss out on the economic opportunity of the 21st century, and many other cities are not only watching and learning, but emulating this example, with new and exciting climate initiatives of their own.
In New York City, Local Law 97 mandates that large buildings cut their carbon footprint. The energy costs of Rio de Janeiro’s municipal buildings will soon be halved by switching to renewables. Amsterdam is on target to phase out natural gas by 2040 while insulating the homes of the city’s most vulnerable residents. Copenhagen is on track to become the first carbon-neutral city by the end of this year, thanks to investments in wind energy and district heating. Across Africa, cities like Nairobi and Freetown are planting millions of trees to cool streets and combat extreme weather.
More than half of the world’s population (56 percent of people) now live in cities, and urban areas generate about 80 percent of global GDP. Throughout history, cities have been hubs of progress on the forefront of innovation. As national governments step back from their climate obligations, cities are now becoming ever-bigger players in the transition to a greener, more environmentally responsible era. They are stepping up and generating not just clean power, but the momentum that’s urgently needed to realize a greener and safer future.
This will hopefully encourage citizens around the world to not lose faith and to continue to put pressure on their national governments to do more before it’s too late.
The first Earth Day mobilized 20 million people to demand action. Today, more than a billion participate annually. So, let’s use this moment to harness our collective power, push back against the vested interests and continue the fight for a better and brighter future for our planet.
Sadiq Khan is the current mayor of London and co-chair of C-40 Cities. Denis Hayes is organizer of the first Earth Day and serves as board chair emeritus of EARTHDAY.ORG.
The views expressed in this article are the writers’ own.