American cities vastly underreport their carbon footprint


Asking each city to build an individual IRS is like developing a national weather forecasting system by asking each county to characterize its local weather and then pull all of those systems together into a cohesive model. “Well, that wouldn’t make sense when you’re doing the weather forecast,” Gurney says. “Likewise, a greenhouse gas emissions system should not be that all entities do it themselves redundantly.

Instead, Gurney argues that the Vulcan system can shoulder the burden of calculating carbon levels for cities in the United States. He and his colleagues have been developing the system for 15 years, incorporating two dozen datasets to meticulously quantify sources of emissions across the country. Vulcan examines traffic, census, and air quality data, and takes an inventory of emissions from all power plants in the United States. In some cities, such as Los Angeles, the model is so detailed that they can discern how the emissions vary. block by block. The team was able to confirm the modeling of Vulcan’s emissions with atmospheric CO measurements2 across the United States.

And in their new research, they found that the city’s self-reports often lag behind the Vulcan results. Their study found that some places, like Flagstaff and Palo Alto, significantly overestimated their emissions (by about 60% and 40%, respectively). Others, like the California city of Torrance, are more than 100% under-reported, according to the study. (The team adjusted Vulcan’s production for each city, by the way. If one omitted industrial fuel consumption, for example, Vulcan would do the same, in order to better reconcile the results. This means that Vulcan would also be under. -estimated., compared to a full report.)

So why is it important to resolve these discrepancies? On the one hand, city agencies can end up spending a lot of time and resources on emissions mitigation – such as creating more transit and green spaces, or making the built environment more user-friendly. pedestrians – so that they have access to the most accurate data possible. on what to finance. And local data is constantly changing as a city naturally transforms over time, so policymakers may find themselves tasked with making decisions based on a recent, already outdated SRI report.

Vulcan, on the other hand, is constantly updated every two or three years with new data across the board, which can characterize a city’s growth over time. “We suggest this should be done on an ongoing basis,” Gurney says. (He says governments can contact his team to start digging into Vulcan’s data on their cities.)

Could Vulcan then become a kind of standardized platform allowing American cities to measure their emissions more precisely? “I think it’s plausible for sure,” said Brian Snyder, environmental scientist at Louisiana State University, who was not involved in the work. “And I think that would be a huge improvement over what they’re doing now.”

Cities are best equipped to transform right now, Snyder says, is transportation. “If you want to reduce your transportation emissions, you need to know what your emissions are to start with,” says Snyder. “And one of the good things Vulcan does is it kind of shows you – very precisely to network space – where they at least think these emissions are coming from. This could help city agencies determine where to strengthen public transport, for example.

But there’s little a city can do to reduce its emissions in the short term, Snyder adds. “A lot of things have been baked in the cake for 100 years.” Oil refineries remain a scar on the landscape for many cities, for example.

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