Improving Characterization of Anthropogenic Methane Emissions in the United States (2018) / Chapter Skim
Currently Skimming:
1 Introduction
1 Introduction
Pages 21-36
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 21... ...
WHY MONITOR, MEASURE, AND TRACK ATMOSPHERIC METHANE AND METHANE EMISSIONS? The effects of increasing concentrations of global methane are diverse and profound.
|
From page 22... ...
Being able to accurately quantify methane emissions and attribute emissions to specific sources is a critical component of addressing climate change.
|
From page 23... ...
Because of methane's short atmospheric lifetimes relative to carbon dioxide, it has been proposed as a target for emission reduction in order to prevent the worst effects of climate change. Reduction of methane emissions, along with reductions in black carbon emissions, could reduce global mean warming by about a half a degree by 2050, with additional benefits for air quality and agricultural productivity (Shindell et al., 2012)
|
From page 24... ...
Methane emission inventories help assess the impact of mitigation strategies and may also help investors benchmark various companies and make informed investment and risk management decisions. METHANE IN THE ATMOSPHERE Analysis of air bubbles trapped in ice cores shows that current levels of methane in the atmosphere are unprecedented over the past two millennia (Loulergue et al., 2008)
|
From page 25... ...
(Top) Analysis of air bubbles trapped in ice cores shows that current levels of atmospheric methane are unprecedented over the past two millennia.
|
From page 26... ...
gases such as methane, mostly predate the last decade of field measurements and modeling, a period during which understanding of methane emissions and sources has significantly advanced. Other types of inventories have emerged recently, such as inventory reports summarizing emissions from certain major emitting sources under the Greenhouse Gas Reporting Program regulations, the spatially explicit (gridded)
|
From page 27... ...
Consequently, atmospheric methane abundance over the United States is significantly influenced by sources located outside of the United States, even though there may be large responses due to strong local emissions. The atmospheric residence time for methane is about a decade; hence emitted methane is redistributed globally, and methane emissions from the United States influence global concentrations.
|
From page 28... ...
. The relatively large contribution of methane from natural sources compels scientists to consider these sources when attributing methane measured via atmospheric samples to the various anthropogenic sources.
|
From page 29... ...
. Although rice cultivation is a significant source of methane emissions globally, it is a relatively minor source in the United 5 Methane emissions resulting from the use and conversion of land use categories in the United States, for example, managed peatlands, coastal wetlands, and forest fires.
|
From page 30... ...
approach involves measuring and/or modeling emissions at the scale of individual methane emitters, such as petroleum and gas wells, landfills, livestock operations, and developing representative emission factors (the estimated mean methane flux per emitter category) for the regional or national activity data (estimated emitter population)
|
From page 31... ...
In the case of bottom-up emission estimates, models are used in a variety of ways, including converting operational and other data on methane emission sources into methane emission estimates (engineering process models) , converting methane measurements distant from a source to emission measurements (atmospheric dispersion models)
|
From page 32... ...
(2014) found that in the petroleum, natural gas, and livestock categories, top-down methane emission estimates consistently exceeded bottom-up inventories by 50-200 percent or more.
|
From page 33... ...
EDGAR = Emissions Database for Global Atmospheric Research; GAINS = Greenhouse gas and Air Pollutant Interactions and Synergies; GHGI = U.S. Greenhouse Gas Inventory.
|
From page 34... ...
In addressing its task, the Committee met five times during early and mid-2017 to discuss the current understanding of U.S. anthropogenic methane emissions across dominant sectors, including key uncertainties and unmet research needs.
|
From page 35... ...
anthropogenic sources of methane emissions in a common language and framework. Two of the meetings, in March and May 2017, were centered around open public workshops that gathered extensive input from scientists across academia, federal and state agencies, industry, and nongovernmental organizations and included site visits to operating petroleum, gas, and agricultural facilities.
|
From page 36... ...
anthro pogenic methane emissions (enteric fermentation, manure management, petroleum and natural gas, landfill, and coal mining) are discussed extensively in Chapters 2, 3, and 4 through the lens of the corresponding chapter topic (inventory development, measuring and monitoring, and uncertainties, respectively)
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.