Increasing urban density could reduce climate change

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Posted at 5:41 PM, Sep 01, 2021

States are starting to re-think the American dream of white picket fences as they build housing with the idea of reducing carbon emissions.

It means a shift away from suburban life and a move toward denser cities.

“We have been hesitant to incorporate greenhouse gas emission planning into our urban development strategies,” said Jay Arehart, professor of civil engineering at the University of Colorado.

According to the Pew Research Center, suburban growth has outpaced city growth over the last 20 years. The study says 16.5 million people moved to the suburbs while 14 million decided to live in cities.

Homes in the suburbs are typically larger than those in the city and, on average, house fewer people: from 3 to 2.5.

According to a study by researchers at the University of Texas, low-density housing produces nearly four times the greenhouse gas emissions of its high-density counterparts.

“It is true that there is a suburban dream in this country. It’s been built up since, arguably, WWII. But it’s also true there’s lots of amenities in cities,” said Dan Kammen, professor of energy at UC Berkeley and director of the CoolClimateNetwork.

To help resolve the issue and build homes with carbon efficiency in mind, states have started incentivizing local governments to change zoning laws that allow for more mixed-use spaces rather than single-family housing.

“A big piece of it is getting rid of obstacles,” said Will Toor, executive director of Colorado’s Energy Office. “We have a vast undersupply of [high density] housing. It’s why the prices are so high. And one big reason is over many of our cities we have very strong zoning constraints that don’t allow new housing to be built.”

In January, Colorado passed two bills. One gives cities $46 million in grants so they can build more high-density housing. The other eases zoning laws, so those buildings can occupy land formerly zoned for single-family use. California recently passed a similar bill, and President Biden has allocated more than $5 billion in incentives to states to ease zoning laws nationwide.

The University of Michigan found doubling urban density could reduce carbon emissions from travel by nearly 50%, and residential energy use by nearly 33%.

“When we have lots of walls that are exposed to the outside, like extra walls of our homes, those transmit more heat and we lose a lot of heat compared where we have more dense settings in apartment complexes, more multi-family type buildings where we are sharing walls,” said Arehart.

With the U.S. targeting to cut greenhouse gas emissions in half by 2030, perhaps it is not just our travel, but where people travel from that will have some of the most significant impacts.