In order for climate change to remain a factor in our economic history rather than a cause in the history of future wars, we need some simple but huge social decisions. One idea is that living in dense cities with mass transit is pleasant and prosperous for people with a range of incomes. New York’s current efforts to reroute drivers and reclaim street space for bikes and pedestrians follows this principle. And by blocking cars from Times Square, an emblem for the city and for urban extravagance, New York has declared this century for humans and for the air we breathe.

But the planners forgot something that fills the air, and its oversight may dilute New York’s influence on other cities.

Don’t misunderstand. I love the new bike lanes in Manhattan’s western and eastern veins. I love the cheery new green stripes on the roadbed, and I love sharing notes with fellow cyclists about the weather or a particularly doofy double-parker. I even love knowing that I can cut through Times Square on my bike or meet there for a business meeting. But when I get to Times Square and navigate its expanse of chairs, something seems too quiet. It’s not the absence of cars. It’s the muting of voices.

TV screens dominate the air over Times Square and chairs and benches rule the ground. I’m calling for a place, even the width of a kiosk, that explicitly invites interaction and exposure through live speaking or unpaid programming, rather than entertainment. This kind of exposure is impossible to price and easy to suppress through the design of public space: suburban cul-de-sacs and long, snaking malls discourage it. But this kind of exposure has sparked cities since Moses (the Israelite, not the Power Broker) yelled from the mountaintop, Ashoka commissioned monuments and the Naked Cowboy rode under the Jumbotron. Our fiercest and sweetest public ideas emerge from public debate, not only from public relaxation.

With all due credit to the project’s success in traffic calming, can’t you both calm traffic and excite the urban spirit?

Picture what a “speakers’ corner,” like the one in London’s Hyde Park, could cultivate in the media capital of America. Public school students could stand on a platform and debate, or upload school projects. Political groups could sign up for it (not rent it- I imagine the city manages its use through a central clearinghouse, like 311). A rule might stipulate that any advertiser in Times Square has to subsidize the upkeep of a speaker’s platform. Of course, much of its use might go to pedants and cranks, like those who turned up at Ross Perot’s town meetings. You can’t legislate lively debate.

But centuries of experience in other world capitals show that you can make the city more thrilling (and more conducive to new solutions) when you invite it. If New York wants to deliver fully on its promise to lead post-carbon cities, it can get a lot of attention and a lot of momentum from a little bit more noise.