1999: Global Methane Inventory

Researchers: Harvey Augenbraun, Teresa Smith, David Sarma, Barrie Portney, Elaine Matthews, and Bernadette Walter

Introduction

The overall goal of this research is to assess the potential

Domestic animals such as cows contribute to atmospheric methane.

contribution of a suite of anthropogenic and natural methane sources to the interannual variation and decadal trend in atmospheric methane concentrations. The following sources are to be investigated: animals, rice, and landfills (anthropogenic), and wetlands (natural) for the period 1980 to the present.

Science Questions

1. What is the trend in atmospheric methane concentrations since measurements began in 1983?
2. What is the 20-year history of three major, anthropogenic, methane sources?
3. What is the 20-year history of wetland emissions, the largest natural source methane?
4. Which sources are candidates to explain the current downward trend in growth rate of atmospheric methane?

Hypotheses

Rice: Since the rice-harvest area has remained essentially constant over the last 10 years, methane emissions from rice are stable.
Domestic animals: Methane emissions have increased with the increase in domestic animal populations.
Landfills: Methane emissions in developed countries are declining and will continue to decline in the future; emissions in developing countries are increasing, and will continue to increase in the future.
Wetlands: Emission from wetlands have increased over the last decade due to warmer temperatures.

Research Tasks

• Locate and obtain data required to estimate annual emissions of methane from animals and rice cultivation for 1985 to the present. (Note: related research will contribute annual methane emissions from landfills (J. Bogner) and wetlands (B. Walter) for the same time period.)
• Use the Intergovernmental Panel of Climate Change (IPCC) methodologies to carry out annual estimates of emissions from the anthropogenic sources.
• Locate, acquire, quality-control, and format data needed for annual inventories of methane from animals and rice for period 1985-present; carry out annual calculations of methane emissions for the period 1985-present for these sources; assess sensitivity of rice-methane estimate to inclusion of management practices; write research results.
• Locate, obtain, organize, and write up historical information on management practices that affect methane emissions from rice cultivation; incorporate new information into rice-methane estimates; assess sensitivity of rice-methane estimate to inclusion of management practices; contribute to writing up team research results.
• Carry out annual calculations of methane emission from wetlands for 1985-present; contribute wetland results and analysis to team; contribute to collection of rice and animal data.