Cities' Self-Reported Emissions Numbers are Way Off, Study Finds

A new study published in Nature Communications claims that cities undercount their greenhouse gas emissions by, on average, close to 20%. If this figure holds across the country, writes John Schwartz in the New York Times, the missed emissions would account for more emissions than the entire state of California produces.

As cities continue to grow and climate change poses increasingly urgent threats, leaders around the world have set emissions-reduction goals, "but there is not yet a consistent way for them to measure the amount of carbon dioxide or to gauge any reduction." As such, the voluntary efforts being undertaken by cities are "inconsistent and flawed." Based on the research team's estimates, the city of Cleveland underreported their emissions by a whopping 90%. Palo Alto, on the other hand, reported emissions 42% higher than the team's estimates, showing a wide range of inaccurate reporting that both under- and over-estimate emissions.

The errors seem to come from "simple miscalculations," but the study's results highlight the need for "a consistent way to state emissions that goes from the city level to the national level." To understand whether a city is moving closer to its climate goals, "accurate measurement is an essential element of knowing where they stand."