An integrated approach for estimating greenhouse gas emissions from 100 U.S. metropolitan areas

Abstract

Cities have become key players in climate change mitigation policy. To develop their climate policies, cities need good assessments of their current and future emissions. We use publically available national datasets to develop an integrated approach for estimating GHG emissions at the metropolitan level over time, between multiple locations, and across sectors. We estimate consistent production-based GHG emissions for the 100 most populated metropolitan areas in the United States in 2014. We find that total 2014 metropolitan CO 2 emissions range from 4.1 million metric tons in Lancaster, Pennsylvania to nearly 170 million metric tons in the Houston, Texas; with an overall average of 27 million metric tons. The top 20 absolute emitters and top 20 per capita emitters only overlap for 9 locations. Per capita emissions also show a wide variation: from 5 metric tons per person in the Tucson, Arizona to 65 metric tons per person in the Baton Rouge, Louisiana; with an overall average of 14 metric tons per person. We also compute estimates for 2002 and 2011 and compare to our 2014 emission estimates. Across all locations analyzed, average total emissions increased by 3% and average per capita emissions decreased by 14%. Where possible, we also compare our emission estimates to those reported by the cities in their climate action plans and find an average absolute difference between our estimates and those reported by the cities of 5.6 metric tons CO 2 per person, likely due to temporal and scope differences between the two estimates. Our integrated emission estimation approach complements bottom-up approaches typically employed by municipalities and helps practitioners divert their attention and resources away from continuous emission accounting toward more impactful emission mitigation efforts.

Better data for assessing local climate policies

“…As such this dataset promises to be of high value for empirical urban climate change research in the future. Markolf et al (2017) find large variations in CO 2 emissions across metropolitan areasthat can range from just over 5 tCO 2 /cap to over 60 tCO 2 /cap. This is due to the production-based inventory method used that accounts for all CO 2 emissions arising from the respective metropolitan territories.…”

“…Those datasets usually do not allow for any meaningful statistical analysis. By providing a large-N sample of comprehensive, consistent and comparable emission inventories for the largest metropolitan areas in the US, Markolf et al (2017) tackle a crucial issue that has hindered progress in learning about local climate actionto date. The resulting data set includes not only a nice cross-section with 100 metropolitan areas, but also spans the period 2002-2014 allowing us to track progress over time.…”

A high-resolution, spatially explicit estimate of fossil-fuel CO2 emissions from the Tokyo Metropolis, Japan

“…Cities are the smallest administrative units appropriate for implementation of climateremediation actions. Previous studies have accounted for city emissions using various approaches, including the purely geographic-based (PB) [9,10], consumption-based carbonfootprint [11,12], and community-wide infrastructure-footprint [13,14] approaches. Such 53 studies estimate emissions for whole cities by monitoring activities at the city level.…”

Emissions and low-carbon development in Guangdong-Hong Kong-Macao Greater Bay Area cities and their surroundings

“…Emission inventories are regarded as important tools for authorities in CO 2 emission mitigation policy formulation and implementation [11][12][13][14][15][16][17]. Citylevel CO 2 emission inventories were compiled by applying bottom-up and top-down approaches from spatial and temporal perspectives [18][19][20][21][22][23][24]. For example, Dhakal [25] selected 35 key Chinese provincial capitals/cities and calculated total energy consumption, CO 2 emissions and average carbon intensity of these cities.…”

“…Kennedy [21] calculated the greenhouse inventories of global 22 cities using a bottom-up approach under the United Framework Convention on Climate Change (UNFCC), variations of emission mitigation strategies result from the differences in cities characteristics were discussed. Xu, Huo [27] Markolf, Matthews [24] calculated production-based GHG emissions for the 100 most populated metropolitan areas in the United States in 2014 based on national datasets. Wang and Liu [28] assessed city-level CO 2 emission based on DMSP/OLS 'city lights' satellite data.…”