by Linda Nash and Jim Hanford
2016 will be the hottest year on record. Atmospheric carbon levels are now higher than they have been in 4 million years. Seattle has admirably made the commitment to carbon neutrality by the year 2050. Locating new housing and businesses near transportation is an important step. But that alone is not enough. One-third of Seattle’s energy use comes from buildings.
In order to achieve carbon neutrality while continuing to grow, the City will have to transition the vast majority of its building stock away from the consumption of electricity and fossil fuels. Yet high-rise construction, as proposed here, is a high-carbon option. Seattle’s own data show that high-rise multi-family buildings currently consume 45% more energy per square foot than mid-rise multi-family and 64% more than low-rise multi-family. In the case of tall buildings, the emphasis on small efficiency improvements and “LEED” certification merely serves to make wasteful construction slightly less unsustainable.
There are significant obstacles to making tall buildings energy and carbon efficient: they require more elevators and air-conditioning; they have more exposure to wind and sun and have higher rates of heat gain and loss; they have a small roof-top area limits the potential to use solar and other renewables. To make matters worse, tall buildings exacerbate the effects of very high temperature days (which we are now experiencing in the summer) by raising surrounding air temperatures and decreasing air flow between buildings. Their long shadows also limit the potential for solar energy on adjacent sites. If Seattle truly wants to mitigate climate change, it will need to prioritize energy considerations in zoning and the design of buildings.
Modern, tower-dominated downtowns emerged in an era of cheap and abundant fossil fuels, and they do not obviously serve the needs of the twenty-first century. Buildings last for many decades and will shape the city’s design and energy needs far into the future. We can’t afford not to get it right.
Read more by Jim Hanford: High-rises are energy hogs, not climate solutions