The Olympic Feat of Urban Sustainability

This week, the eyes of the world are on the city of Rio de Janeiro, as visitors and Cariocas alike revel in the celebration of an historic moment: the first time the Olympics and Paralympics Games have ever been held in South America.

The Games are all about competition between individuals, teams and nations. We cheer for our nations and delight in the competitive spirit of the games. And yet, when we speak of the Olympics, we don't discuss host countries -- we talk instead about host cities. And the Olympic Games are only one example of how cities are commanding greater influence on the national stage, an evolution that has significant implications for our global community.

While nations go to great lengths to best other countries in everything from economic growth to football, the story at the city level is quite the contrary: it is a quiet but powerful story of collaboration and cooperation, especially when it comes to taking action against climate change.

As megacity mayors, we have long considered cities laboratories for great ideas, but it wasn't until the COP21 climate negotiations in Paris last year that we recognized the scope of our capacity as local leaders to influence the course of the planet. World leaders made a commitment through the Paris Agreement, but it's up to cities to deliver on that ambition and prevent runaway climate change. How cities develop in the coming years will set the stage for humanity as a whole.

The good news is that for more than a decade, the mayors of the world's megacities have come together with passion and momentum to share knowledge and drive measurable and sustainable action on climate change through the C40 Cities Climate Leadership Group (C40). Today, 85 cities are members of the network, representing 650 million people and a quarter of the world's economy.

Created and led by cities, C40 is focused on tackling climate change and driving urban action that reduces greenhouse-gas emissions -- C40 cities have already committed to reducing their emissions by a total of more than 3 gigatons of C0 by 2030 -- the equivalent of taking 600 million cars off the road. Mayors are sharing ideas, driving ambition and creating the momentum that will be essential in keeping the increase in global temperatures below 1.5 degrees Celsius above preindustrial levels.

Crucially, the exchange of ideas between cities is genuinely global. More than half of the cities in the C40 network are from Latin America, Asia, Africa and the Middle East -- these city leaders are showing incredible commitment to low-carbon development and climate action.

VIDEO: In anticipation of the Olympic Games, Rio has prioritized legacy projects -- investments in or improvements to the city, like improved public transport -- that will directly benefit the people of Rio. For every one Real they have spent on the Olympic Games, they have invested five Reais on ensuring a sustainable legacy for the city.

And cities are taking every opportunity to pursue the twin goals of urban sustainability and economic growth. For Rio, the Olympics have given us the chance to coordinate all efforts toward a common goal: an eye toward a better future for the city. The Games provided Rio with an opportunity to move toward a more sustainable, equitable and green future, enhancing urban mobility, fortifying and unifying the city's data systems, revitalizing neglected areas of the city and undertaking some of the most ambitious legacy projects an Olympic City has ever seen.

Though Paris is a much older and more storied city, we have found innovative ways to welcome the principles of sustainability to its heart: closing the iconic Champs-lyses to cars once a month, pedestrianizing the banks of the Seine, retrofitting buildings and establishing a citywide long-term emissions-reduction goal.

As the star power from the Paris climate talks fades, city leaders are in the trenches, tackling the daily challenges of a city's needs while creating the framework for long-lasting commitments to building cities healthier, safer and greener.

In fact, at the end of this year, mayors, urban experts, businesspeople and celebrities from around the world will come together at the C40 Mayors Summit in Mexico City. There, delegates will work to continue positioning cities as a leading force for climate action around the world, defining and amplifying their call to national governments for greater support and autonomy in delivering climate action and creating a sustainable future.

Exactly one year since the COP21 climate negotiations in Paris, these leaders in the global effort against climate change will once again provide the vision and inspiration to political leaders everywhere to deliver on the Paris Agreement. As the current Chair and Chair-Elect of C40, we are determined to see the world's largest and most influential cities continue to mobilize to deliver on this promise. Our ambition is not only to create low-carbon cities that are safe against the shocks of a rapidly warming world, but to deliver sustainable, equitable and healthy futures for millions of urban citizens worldwide.

*Anne Hidalgo, Mayor of Paris, was recently elected to succeed Eduardo Paes, Mayor of Rio De Janeiro, as Chair of the C40 Cities Climate Leadership Group. Mayor Hidalgo will take the role in December 2016.