With the news that San Francisco is now mandating solar panels on new construction of certain sizable buildings, Brad Plumer over at Vox makes the point that the city could save more carbon emissions by allowing greater housing density:

According to a 2015 report from UCLA, the average person in the city of San Francisco emits just 6.7 metric tons of CO2 per year. By contrast, the average person who lives in the Bay Area emits 14.6 metric tons of CO2 per year. (The national average is about 17 metric tons.) So if San Francisco relaxed its restrictions and enabled, say, an additional 10,000 people to move from elsewhere in the Bay Area to the city, we could expect that to cut 79,000 metric tons of CO2 per year (to a first, crude approximation). This is three times as much CO2 as the solar panel law would save.

On a related subject, Shane Phillips rails against supposedly pro-environment, liberal coastal enclaves like San Francisco revolting against this kind of housing density:

According to a 2015 NYU Furman Center report, rents and housing prices have climbed much more rapidly than incomes in places like NY, SF, and LA, while the reverse is true in places like Dallas, Houston, and Atlanta. Even without referring to the data, we’re all painfully aware of how quickly places like D.C. and San Francisco have become out of reach for lower-income, working class, and even many middle class households. This has had a disparate impact on people of color, the elderly, and other disadvantaged or vulnerable populations—and it’s happening in exactly the places that claim to care most about supporting these individuals.

I couldn’t agree more, but with one caveat: we can’t expect a relatively small city like San Francisco to assume all the responsibility for housing new residents in the Bay Area. Given its abundance of transit, it does make sense for the city to assume something like the majority of new growth, but Silicon Valley, Oakland, Berkeley, and anyplace with a BART station needs to step up, too.

Finally, I’ll just note that for those who complain that California makes it unduly difficult to build housing with laws like CEQA, it’s interesting to see how this housing shortage in urban areas is a national phenomenon. Not that reform of state laws isn’t needed, but it puts the problem in perspective.