Science & Tech

Cities can help turn the world green

6 min read

Can green cities save a blue planet?

That question was posed last week by Harvard climatologist Daniel Schrag, director of Harvard’s Center for the Environment. The professor of Earth and planetary sciences and professor of environmental science and engineering was one of three technical experts who spoke at a conference March 5 — co-sponsored by Harvard and the city of Boston — on the regional impacts of global warming.

The short answer: Cities can help. For one, the experts say, they generate 75 percent of the greenhouse gases contributing to climate change. And cities are the teeming brains of the world — “incredible focal points for innovation,” said Schrag.

Regionally, two cities are doing what they can to save the planet.

Boston is one. This month, Beantown was named the third-greenest city by Popular Science magazine — in part for a 2007 green building requirement for all new construction. And last week Boston released its climate action plan, calling for increased bike traffic, more open space, and expanded requirements for green building standards.

“Urban areas are the economic engines of America,” said Boston Mayor Thomas M. Menino, who opened the conference with remarks to a capacity crowd at the Boston Public Library’s Rabb Lecture Hall. “While climate change is a global issue, we can do our part.”

The other “city” going for the green is Harvard, with its thousands of students and its many laboratories and teaching facilities. The centuries-old University, like its host communities, is focused on its environmental footprint. Harvard consumes energy, treats waste, and expands its building stock according to sustainability principles adopted in 2004.

And more dashes of green are being added to crimson. Last month (Feb. 27), Harvard President Drew Faust, who is also Lincoln Professor of History, appointed a task force to identify a goal for reducing greenhouse gas emissions. It will report its findings to her by June.

“Harvard has an important responsibility to confront these challenges,” said Faust of regional changes that impact global warming. “Local policies may be effective, where broader policies may not be viable.”

Centers of higher education bear a special responsibility in dealing with environmental issues, she said. First, there is the capacity for scholarship. (Faust praised the Center for the Environment as an “interdisciplinary hub for environmental education.”)

Then there is the capacity for direct action. Faust outlined a few of Harvard’s contributions, including a 50 percent-plus recycling rate, a low incidence of single-occupancy commuter car travel (18 percent), and Harvard Dining Services, which purchases 40 percent of its food from regional producers.

Faust also praised the Boston-Harvard collaboration in planning for the University’s campus in Allston. “Cities, like universities, are learning laboratories,” she said. “We are stronger when we are united on this front.”

Menino and Faust “want real progress, right away,” said moderator David T. Ellwood, dean of Harvard’s John F. Kennedy School of Government.

The two leaders traded praise. Menino called the two-year Allston planning process “an exceptional experience.”

Faust called the town-gown cooperation “an affirmation of the very important partnership between cities and universities.”

The initial phase of the Allston project, she said, will transform 30 acres of paved surfaces into new open space, construct sustainable buildings, and require reduced energy consumption, CO2 emissions, and storm water runoff.

Schrag led off the technical part of the program by imparting a sense of the scale of the global warming problem. In a word: huge.

Levels of CO2 in the atmosphere — the chief culprit of climate change — are higher than they have been in 650,000 years, and are likely higher than in the past 35 million years.

Preindustrial levels of the compound hovered around 280 parts per million (ppm), are 385 ppm today — and will be around 500 ppm in as little as 40 years. “This is not a debate,” said Schrag. “We will see huge climate change this century,” including a summertime Artic Ocean that is ice-free within a decade.

He said atmospheric change is driven by fossil fuels, where humans get 85 percent of their energy, and it’s also “a profound geological experiment.” Likely impacts include droughts, heat waves, more violent storms and floods, and rises in sea level.

Schrag showed a bird’s-eye projection of Boston in the event of a 0.6-meter rise in sea level. It looked like Venice.

There are three categories of solutions, said Schrag, “and we need them all”: reduced energy use, new sources of non-carbon energy, and a way to sequester excess CO2 in geological formations.

There are some reasons to be optimistic, he said. Fixing only 1,000 power plants worldwide, for one, would address the source of nearly a third of greenhouse gases. And rebuilding energy infrastructure worldwide would cost only 1 to 2 percent of global revenues. That’s as much as $200 billion in U.S. GDP, said Schrag — a huge investment, but a business opportunity too.

Presenter and urban economist Edward Glaeser, Harvard’s Glimp Professor of Economics and director of the Rappaport Institute for Greater Boston, likes the idea of “emissions accounting” as a way of knocking down energy use, especially in fast-growing urban centers. Glaeser, who is also director of the Taubman Center for State and Local Government, is in favor of a carbon tax, too, and steeper taxes for roadways.

“Car-heavy places have grown more quickly” in the past 20 years, he said, pushing roadways deeper into areas of low-density population. Suburbs, in turn, consume more per capita energy, gasoline included, than their urban counterparts.

Land use planning counts, said Glaeser. Living in Boston is a relatively green experience, he said, but “once you hit Waltham, you’re in full suburban-energy use.”

Presenter James W. Hunt III is all in favor of the urban experience as a green experience, but acknowledges a steady flight to the suburbs too. “City living is green,” said Hunt, chief of Boston’s environmental and energy services, and a lifetime Dorchester resident. “But we have to encourage our residents to stay here.”

That means keeping the urban core more livable and inviting, he said, in part through forward-thinking environmental planning. That includes a Boston plan to add 100,000 new trees by 2020, scrubbing the air and reducing the urban “heat island” effect that spikes temperatures by 10 degrees or more.

The city already has an impressive 29 percent of tree cover, said Hunt, but “it’s a tale of two cities.” Most of the trees are in wealthier areas.

Hunt enumerated other ways Boston is planning for a future that will help ward off sea level rise, devastating storms, and a sun-cooked urban core: Boston initiatives that reduce greenhouse gases by 2050 to 80 percent of 1990 levels; a Boston green jobs industry already growing by 20 percent a year; plans for more energy conservation and solar power; and green building requirements “hardwired into the zoning” for new construction, said Hunt — 6 million square feet of new buildings in 2007, and 4 million more square feet in the pipeline.

Ellwood summed up the challenge of making cities an engine for change in global warming: “The really inconvenient truth,” he said, “is that it is hard and not easy — expensive and not cheap.”