If architects, planners, and public officials in Boston mean everything they say about sustainability and climate readiness, why is the city’s latest construction boom filling the skyline with so much glass? From the shimmering height of the Millennium Tower to the waterfront views of 22 Liberty, and a boxy office and condo complex going up at Pier 4, glass exteriors have become a major feature of today’s urban landscape. Just as we associate periods in Boston’s history with specific materials and styles — like 19th-century brick apartment blocks and 20th-century monumental concrete forms — glass is the material of the moment. The new buildings mimic others being erected in New York, London, Dubai, Singapore, and other cities around the world. Glass walls have become a shortcut for architecture that is sleek, cosmopolitan, and of-the-moment.
Yet glass buildings also take a lot of energy to heat and cool. When New York started tracking energy use by skyscrapers, the gleaming 7 World Trade Center — one of that city’s more efficient glass towers — scored worse than the 1930s-era Empire State Building. Oddly, glass buildings are proliferating even as cities like Boston set ambitious goals to deal with climate change. Former mayor Thomas Menino vowed to cultivate “the most sustainable city in the United States”; his successor, Martin Walsh, has called Boston “America’s climate champion” and set a goal of being carbon neutral by 2050.