Informing urban climate planning with high resolution data: the Hestia fossil fuel CO2 emissions for Baltimore, Maryland

Geoffrey S Roest,J Liang,S M Miller,K R Gurney

doi:10.1186/s13021-020-00157-0

Abstract

BackgroundCities contribute more than 70% of global anthropogenic carbon dioxide (CO2) emissions and are leading the effort to reduce greenhouse gas (GHG) emissions through sustainable planning and development. However, urban greenhouse gas mitigation often relies on self-reported emissions estimates that may be incomplete and unverifiable via atmospheric monitoring of GHGs. We present the Hestia Scope 1 fossil fuel CO2 (FFCO2) emissions for the city of Baltimore, Maryland—a gridded annual and hourly emissions data product for 2010 through 2015 (Hestia-Baltimore v1.6). We also compare the Hestia-Baltimore emissions to overlapping Scope 1 FFCO2 emissions in Baltimore’s self-reported inventory for 2014.ResultsThe Hestia-Baltimore emissions in 2014 totaled 1487.3 kt C (95% confidence interval of 1158.9–1944.9 kt C), with the largest emissions coming from onroad (34.2% of total city emissions), commercial (19.9%), residential (19.0%), and industrial (11.8%) sectors. Scope 1 electricity production and marine shipping were each generally less than 10% of the city’s total emissions. Baltimore’s self-reported Scope 1 FFCO2 emissions included onroad, natural gas consumption in buildings, and some electricity generating facilities within city limits. The self-reported Scope 1 FFCO2 total of 1182.6 kt C was similar to the sum of matching emission sectors and fuels in Hestia-Baltimore v1.6. However, 20.5% of Hestia-Baltimore’s emissions were in sectors and fuels that were not included in the self-reported inventory. Petroleum use in buildings were omitted and all Scope 1 emissions from industrial point sources, marine shipping, nonroad vehicles, rail, and aircraft were categorically excluded.ConclusionsThe omission of petroleum combustion in buildings and categorical exclusions of several sectors resulted in an underestimate of total Scope 1 FFCO2 emissions in Baltimore’s self-reported inventory. Accurate Scope 1 FFCO2 emissions, along with Scope 2 and 3 emissions, are needed to inform effective urban policymaking for system-wide GHG mitigation. We emphasize the need for comprehensive Scope 1 emissions estimates for emissions verification and measuring progress towards Scope 1 GHG mitigation goals using atmospheric monitoring.

Highlights

Cities contribute more than 70% of global anthropogenic carbon dioxide (CO2) emissions and are leading the effort to reduce greenhouse gas (GHG) emissions through sustainable planning and development
The Hestia-Baltimore v1.6 F FCO2 emissions data product stems from Vulcan v3.0—a national-scale Fossil-fuel carbon dioxide (FFCO2) emissions data product with emissions disaggregated by sectors, fuel types, and processes [16]
The sectoral emission totals in the City of Baltimore were incorporated into the Hestia-Baltimore system and distributed in space and time using local data sources where available

Summary

Introduction

Cities contribute more than 70% of global anthropogenic carbon dioxide (CO2) emissions and are leading the effort to reduce greenhouse gas (GHG) emissions through sustainable planning and development. In order to meet their stated goals, cities typically start with an inventory of their baseline emissions following one of a few established protocols and inventory tools that accompany them These protocols/tools are often developed by non-governmental organizations to assist cities with the baseline inventory process and reflect the entire-city scale within broad sectoral categories (We refer to these inventories as ‘self-reported inventories’—SRIs). While these tools are relatively simple and accessible, limitations in data, city staff time, and budget constraints mean that the methods, baseline year, estimation quality and comprehensiveness, vary from city to city. This mixture may accommodate city-specific emissions policies or monitoring requirements, but it limits the ability of the SRIs to be compared to atmospheric monitoring, the only current means to independently evaluate emissions and provide constructive feedback on the uncertainties in Scope 1 emissions to city planners [9, 10]

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