Report Finds Providence’s Estimates of Climate Emissions 60% Greater than Reported
February 21, 2021
A number of recent reports suggest that Rhode Island is underestimating its greenhouse gas emissions. The results may challenge the state’s ability to meet its targets for reducing climate emissions.
Providence may be underreporting its greenhouse gas emissions by 60 percent, according to one report. The enormity of that error makes Providence the city with the fifth-most inaccurate estimate of climate emissions in the country.
Cities dominate the emitting of climate emissions and Providence is one that self-reports an estimate of its emissions. Rhode Island’s capital is hardly the only city that does so.
Cities across the globe estimate their greenhouse-gas emissions, which are referred to as “self-reported inventories” (SRIs). However, there is no systematic, reliable assessment of the quality or accuracy of these estimates, even though such data are vitally important in establishing targets for greenhouse gas mitigation activities.
A report published this month in the scientific journal Nature Communications compares self-reported inventories from 48 U.S. cities to independent estimates from the Vulcan carbon dioxide emissions dataset.
The overall average of the underreporting is about 18 percent for the 48 cities studied. That makes Providence’s underreporting error more than three times worse than the national average.
The Vulcan dataset reports U.S. fossil fuel carbon dioxide emissions from factories, power plants, transportation, and cement manufacturing for the entire country from 2010 to 2015. The Vulcan results are accurate and agree within a couple of percentage points of several other data sources.
If the report’s 18 percent underreporting error is extrapolated to all cities in the United States, the total underreported greenhouse gas emissions could be 24 percent larger than the entire emissions from the state of California in 2015.
Many cities are taking a leadership role in mitigating climate emissions by pledging ambitious greenhouse-gas reduction goals. As a result, cities are playing an increasingly important role in the international climate-change negotiating process.
Estimating greenhouse-gas emissions is a costly endeavor, placing yet another burden on city staff and resources. Data collection, processing, and modeling present technical challenges, which burdens available resources and contributes to incomplete and inaccurate estimates.
This emissions data comes on top of a 2019 report by the Stockholm Environmental Institute and Brown University’s Climate & Development Lab that argues Rhode Island has been underestimating the severity of gas leaks, which occur at nearly every part of the gas production and distribution process.
Natural gas is about 80 percent methane, an extremely potent greenhouse gas. Therefore, small differences in leakage rates can have massive impacts on emissions estimates. The Stockholm Environmental Institute and Brown University report says that better accounting of gas leakage rates results in a 45 percent increase in overall state emissions.
Rhode Island’s Office of Energy Resources leads the state’s efforts to reduce greenhouse-gas emissions. The State Planning Council voted six years ago to adopt Rhode Island’s new energy plan, Energy 2035, codifying the state’s long-term energy strategy.
The plan’s vision is to provide energy services across all sectors — electricity, thermal, and transportation — using a secure, cost-effective, and sustainable energy system. The plan’s modeling shows that viable paths exist for Rhode Island to shift to a sustainable, low-carbon future, while simultaneously producing net economic benefits.
Rhode Island’s plan includes strategies, programs, and actions to meet ambitious targets for greenhouse gas emissions: 10 percent below 1990 levels by 2020; 45 percent below 1990 levels by 2035; and 80 percent below 1990 levels by 2050. (A bill has been introduced during the current General Assembly session that makes, among other things, emissions targets line up with the latest science.)
If the underestimates of Rhode Island’s greenhouse-gas emissions are accurate, it would significantly impact the state’s ability to achieve its climate emission reduction goals.
Roger Warburton, Ph.D., is a Newport, R.I., resident. He can be reached at [email protected]
References: Gurney, K.R., Liang, J., Roest, G. et al. Under-reporting of greenhouse gas emissions in U.S. cities. Nature Communications 12, 553 (2021). DOI: https://www.nature.com/articles/s41467-020-20871-0; and Vulcan Data High-Resolution Annual Fossil Fuel CO2 Emissions in USA, 2010-2015, Version 3, Gurney, K.R., J. Liang, R. Patarasuk, Y. Song, J. Huang, and G. Roest. 2019. ORNL DAAC, Oak Ridge, Tennessee, USA. https://doi.org/10.3334/ORNLDAAC/1741.
Editor’s note: This story was updated Feb. 24.