Atmospheric Methane Sources Sinks And Role In Global Change

Methane plays many important roles in the earth's environment. It is a potent "greenhouse gas" that warms the earth; controls the oxidizing capacity of the atmosphere (OH) indirectly affecting the cycles and abundances of many atmospheric trace gases; provides water vapor to the stratosphere; scavenges chlorine atoms from the stratosphere, terminating the catalytic ozone destruction by chlorine atoms, including the chlorine released from the man-made chlorofluorocarbons; produces ozone, CO, and CO2 in the troposphere; and it is an index of life on earth and so is present in greater quantities during warm interglacial epochs and dwindles to low levels during the cold of ice ages. By all measures, methane is the second only to CO2 in causing future global warming. The book presents a comprehensive account of the current understanding of atmospheric methane, and it is an end point for summarizing more than a decade of intensive research on the global sources, sinks, concentrations, and environmental role of methane.

Methane is an important greenhouse gas that can cause global warming. The present concentrations of methane are nearly three times higher than several hundred years ago. Today, more than 60% of the atmospheric methane comes from human activities, including rice agriculture, coal mining, natural gas usage, biomass burning, and raising of cattle. Methane affects the stratospheric ozone layer and the oxidizing capacity of the atmosphere, which in turn control the concentrations of many man-made and natural gases in the atmosphere. This book brings together our knowledge of the trends and the causes behind the increased levels of methane. Based on the scientific information on the sources and sinks, and the role of methane in global warming, strategies to limit emissions can be designed as part of a program to control future global warming.

Understanding, quantifying, and tracking atmospheric methane and emissions is essential for addressing concerns and informing decisions that affect the climate, economy, and human health and safety. Atmospheric methane is a potent greenhouse gas (GHG) that contributes to global warming. While carbon dioxide is by far the dominant cause of the rise in global average temperatures, methane also plays a significant role because it absorbs more energy per unit mass than carbon dioxide does, giving it a disproportionately large effect on global radiative forcing. In addition to contributing to climate change, methane also affects human health as a precursor to ozone pollution in the lower atmosphere. Improving Characterization of Anthropogenic Methane Emissions in the United States summarizes the current state of understanding of methane emissions sources and the measurement approaches and evaluates opportunities for methodological and inventory development improvements. This report will inform future research agendas of various U.S. agencies, including NOAA, the EPA, the DOE, NASA, the U.S. Department of Agriculture (USDA), and the National Science Foundation (NSF).

In this first comprehensive handbook of the earth's sinks for greenhouse gases, leading researchers from around the world provide an expert synthesis of current understanding and uncertainties. It will be a valuable resource for students, researchers and practitioners in conservation, ecology and environmental studies.

While a number of gases are implicated in global warming, carbon dioxide is the most important contributor, and in one sense the entire phenomena can be seen as a human-induced perturbation of the carbon cycle. The Global Carbon Cycle offers a scientific assessment of the state of current knowledge of the carbon cycle by the world's leading scientists sponsored by SCOPE and the Global Carbon Project, and other international partners. It gives an introductory over-view of the carbon cycle, with multidisciplinary contributions covering biological, physical, and social science aspects. Included are 29 chapters covering topics including: an assessment of carbon-climate-human interactions; a portfolio of carbon management options; spatial and temporal distribution of sources and sinks of carbon dioxide; socio-economic driving forces of emissions scenarios. Throughout, contributors emphasize that all parts of the carbon cycle are interrelated, and only by developing a framework that considers the full set of feedbacks will we be able to achieve a thorough understanding and develop effective management strategies. The Global Carbon Cycle edited by Christopher B. Field and Michael R. Raupach is part of the Rapid Assessment Publication series produced by the Scientific Committee on Problems of the Environment (SCOPE), in an effort to quickly disseminate the collective knowledge of the world's leading experts on topics of pressing environmental concern.

"Methane is a powerful greenhouse gas and is estimated to be responsible for approximately one-fifth of man-made global warming. Per kilogram, it is 25 times more powerful than carbon dioxide over a 100-year time horizon -- and global warming is likely to enhance methane release from a number of sources. Current natural and man-made sources include many where methane-producing micro-organisms can thrive in anaerobic conditions, particularly ruminant livestock, rice cultivation, landfill, wastewater, wetlands and marine sediments. This timely and authoritative book provides the only comprehensive and balanced overview of our current knowledge of sources of methane and how these might be controlled to limit future climate change. It describes how methane is derived from the anaerobic metabolism of micro-organisms, whether in wetlands or rice fields, manure, landfill or wastewater, or the digestive systems of cattle and other ruminant animals. It highlights how sources of methane might themselves be affected by climate change. It is shown how numerous point sources of methane have the potential to be more easily addressed than sources of carbon dioxide and therefore contribute significantly to climate change mitigation in the 21st century."--Publisher's description.

In this first comprehensive handbook of the earth's sinks for greenhouse gases, leading researchers from around the world provide an expert synthesis of current understanding and uncertainties. It will be a valuable resource for students, researchers and practitioners in conservation, ecology and environmental studies.

The Changing Atmosphere F. S. Rowland I. S. A. Isaksen Editors The global distribution of a large number of trace gases and aerosol particles is changing. Many of these species are of importance for the Earth’s climate and the oxidation capacity of the atmosphere. Changes may therefore be important in the future for a wide range of environmental problems such as global temperature changes, the oxidation of acidic species, formation of photochemical oxidants, and depletion of the stratospheric ozone layer. In this volume four specific areas directly related to these problems are discussed: (a) how the atmosphere has already changed, (b) the oxidizing capacity of the atmosphere, (c) changes in the Antarctic ozone, and (d) trace substances and radiation balance of the Earth. The authors of the background papers and the group reports discuss the state of knowledge in these four areas, with special emphasis on possible changes that have occurred in the global distribution of trace gases and aerosol particles as a result of human activities. This volume should appeal, in particular, to scientists working in the fields of atmospheric chemistry and physics, meteorology, and those interested in environmental issues such as climate change, ozone depletion, and tropospheric pollution.