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.

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.

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.

The impact on climate from 200 years of industrial development is an everyday fact of life, but did humankind's active involvement in climate change really begin with the industrial revolution, as commonly believed? Plows, Plagues, and Petroleum has sparked lively scientific debate since it was first published--arguing that humans have actually been changing the climate for some 8,000 years--as a result of the earlier discovery of agriculture. The "Ruddiman Hypothesis" will spark intense debate. We learn that the impact of farming on greenhouse-gas levels, thousands of years before the industrial revolution, kept our planet notably warmer than if natural climate cycles had prevailed--quite possibly forestalling a new ice age. Plows, Plagues, and Petroleum is the first book to trace the full historical sweep of human interaction with Earth's climate. Ruddiman takes us through three broad stages of human history: when nature was in control; when humans began to take control, discovering agriculture and affecting climate through carbon dioxide and methane emissions; and, finally, the more recent human impact on climate change. Along the way he raises the fascinating possibility that plagues, by depleting human populations, also affected reforestation and thus climate--as suggested by dips in greenhouse gases when major pandemics have occurred. While our massive usage of fossil fuels has certainly contributed to modern climate change, Ruddiman shows that industrial growth is only part of the picture. The book concludes by looking to the future and critiquing the impact of special interest money on the global warming debate. In the afterword, Ruddiman explores the main challenges posed to his hypothesis, and shows how recent investigations and findings ultimately strengthen the book's original claims.

The world's nations are moving toward agreements that will bind us together in an effort to limit future greenhouse gas emissions. With such agreements will come the need for all nations to make accurate estimates of greenhouse gas emissions and to monitor changes over time. In this context, the present book focuses on the greenhouse gases that result from human activities, have long lifetimes in the atmosphere and thus will change global climate for decades to millennia or more, and are currently included in international agreements. The book devotes considerably more space to CO2 than to the other gases because CO2 is the largest single contributor to global climate change and is thus the focus of many mitigation efforts. Only data in the public domain were considered because public access and transparency are necessary to build trust in a climate treaty. The book concludes that each country could estimate fossil-fuel CO2 emissions accurately enough to support monitoring of a climate treaty. However, current methods are not sufficiently accurate to check these self-reported estimates against independent data or to estimate other greenhouse gas emissions. Strategic investments would, within 5 years, improve reporting of emissions by countries and yield a useful capability for independent verification of greenhouse gas emissions reported by countries.

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.