Mayor Bloomberg’s time in office may be term-limited to eight years, but his Earth Day speech yesterday made it clear that he wants a permanent impact on the city.

The mayor outlined a sweeping program of 127 green growth policies that will help both New York and the environment. He continued his fight for more housing, because more energy efficient homes in New York will mean fewer gas guzzling residences and drivers in the exurbs. He promised to transform the city into a more environmentally friendly place, with more parks and fewer brownfields.

Courageously, he called for a congestion charge of $8 on cars driving below 86th Street during the daytime. These are bold proposals that represent the best in city government — putting the needs of the entire city, and indeed the country, first. Much of the city will be needed in the fight, alongside the mayor, to implement these policies, which will make New York both bigger and greener.

The mayor needs this help because he needs the approval of the state Legislature to implement some of his proposals, like the congestion charge. Special interest groups are already lobbying and misleading in order to sabotage this policy, which would be good for air quality, commute times and especially Manhattan’s least fortunate.

The intuition of a congestion charge is that there are two ways of giving access to valuable goods, like city streets. First, one can use the price system and charge cash. This is the technique used in the free market, and it works well. The people who value a good most buy it, and we don’t waste time on lines. Second, one can give the goods away for free to people who queue up. This is the old Soviet system, and it wasn’t a success. People spent hours waiting in line, often to get nothing after all that time.

Our current traffic system follows the old Soviet model. We give away access to city streets with charging any cash, and as a result people pay with their time. Billions of hours are wasted each year in New York traffic. A congestion charge would make city streets much faster, as it has in London, and the charge could be used for something worthwhile, like tax refunds

The most shameful canard that about congestion charging is that it is bad for the poor. This is utter nonsense. The biggest winners from congestion pricing are the poorer (and richer) New Yorkers who take buses. They will pay no charge and will ride to work more quickly. The enthusiasm of London’s mayor, “Red” Ken Livingstone, for the congestion charge was predicated in part on its ability to help his poorer constituents. His enthusiasm has been completely vindicated.

Congestion pricing will also improve air quality in the city by reducing the number of cars. It is just one of the mayor’s many ideas to improve New York’s environment. These policies are just as much good urban development policy as they are good environmentalism. New York must compete to attract the smart, creative people that drive its economy. Fixing the hangovers of the city’s manufacturing past is an important step in ensuring the city’s future as a center of ideas and innovation.

New York’s 19th century growth came from manufacturing industries built around its port. Sugar refining was our most lucrative industry in the early 19th century, and its location in New York reflected the city’s role as the port of entry for Caribbean sugar. The garment trade was based on the cotton, textiles, and immigrants that came through the harbor. While these and other manufacturing industries created jobs and fortunes, they were also hard on the city’s air, land and water.

As changes in transportation technology made it easier to make clothes, sugar, and most other goods elsewhere, manufacturing jobs left New York, but left their environmental consequences behind. As the city moved from making goods to making ideas, our industrial legacy came to be increasingly at odds with a New York that no longer needs to pollute to produce. By cleaning up brownfields and making the waterfront accessible to recreation, Mr. Bloomberg is trying to adapt the city and enable it to thrive as a consumer city that will attract innovative people.

While it is good environmentalism to clean up brownfields, the best thing New York City can do for the environment is just to grow. Living in high rises and taking public transportation is good for our climate. Living amidst trees in large houses and driving scores of miles is not. As the mayor said yesterday “by absorbing nearly a million more residents by 2030 into one of the world’s most efficient places to live, we will prevent more than 15 million metric tons of greenhouse gases from being released into the atmosphere each year.”

The mayor was right and I hope we can all help him fight for a bigger and greener New York. Let’s celebrate every future Earth Day by permitting another environmentally friendly 50-story high rise building on the Island of Manhattan.

Mr. Glaeser, a professor of government at Harvard University and a fellow of the Manhattan Institute, is a contributing editor of The New York Sun.