A thought experiment compares the carbon impact of three new single family homes with the same block if it contained a duplex, a triplex, and a fourplex.

If it were legal everywhere, Michael Anderson writes, gentle density would confer massive carbon savings and ease the transition away from fossil fuels.
To illustrate, Anderson poses a thought experiment where three large new homes are constructed on one block, while a duplex, triplex, and fourplex are built on a site of the same size. "If we compare these two blocks after all the new homes are complete, the housing-related carbon emissions per household of the Plex Block will be about 20 percent lower," he writes.
It makes sense that smaller living spaces cost less carbon (and dollars) to heat in the winter and cool in the summer. And in the case of the McMansion, most of that space isn't even lived in.
Anderson also notes that when "missing middle" housing is permitted, the positive environmental effects extend to transportation. "This density effect is probably strongest if it's creating new options for living in a transit-rich, walkable area specifically for people who want to live a low-car life but couldn't previously afford that sort of neighborhood."
FULL STORY: A DUPLEX, A TRIPLEX AND A FOURPLEX CAN CUT A BLOCK’S CARBON IMPACT 20%

Study: Maui’s Plan to Convert Vacation Rentals to Long-Term Housing Could Cause Nearly $1 Billion Economic Loss
The plan would reduce visitor accommodation by 25,% resulting in 1,900 jobs lost.

North Texas Transit Leaders Tout Benefits of TOD for Growing Region
At a summit focused on transit-oriented development, policymakers discussed how North Texas’ expanded light rail system can serve as a tool for economic growth.

Using Old Oil and Gas Wells for Green Energy Storage
Penn State researchers have found that repurposing abandoned oil and gas wells for geothermal-assisted compressed-air energy storage can boost efficiency, reduce environmental risks, and support clean energy and job transitions.

Private Donations Propel Early Restoration of Palisades Playground
Los Angeles has secured over $1.3 million in private funding to restore the Pacific Palisades playground months ahead of schedule, creating a modern, accessible space that supports community healing after recent wildfires.

From Blight to Benefit: Early Results From California’s Equitable Cleanup Program
The Equitable Community Revitalization Grant (ECRG) program is reshaping brownfield redevelopment by prioritizing projects in low-income and environmental justice communities, emphasizing equity, transparency, and community benefits.

Planting Relief: Tackling Las Vegas Heat One Tree at a Time
Nevada Plants, a Las Vegas-based nonprofit, is combating the city’s extreme urban heat by giving away trees to residents in underserved neighborhoods, promoting shade, sustainability, and community health.
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