1997: Global Methane Inventory

Team Members: Harvey Augenbraun, David Sarma, Elaine Matthews

Background

Methane is an effective greenhouse gas whose atmospheric concentrations are increasing. Anthropogenic activities (e.g., rice cultivation, waste generation, coal mining, production, transmission, and consumption of oil and natural gas) dominate the total annual methane source. Increasing anthropogenic sources probably contribute to observed increases in atmospheric concentration and variations in temperature and precipitation may be affecting methane emissions from natural wetlands and from irrigated rice fields. A suite of 2- and 3-dimensional models to analyze the chemical dynamics to the atmosphere exists. Seasonal and spatial distributions of methane emissions are some of the inputs to these spatially distributed models. Recognizing the data needs of modelers, the International Global Atmospheric Chemistry (IGAC) project of IGBP (International Geosphere-Biosphere Programme) initiated the Global Emissions Inventory Activity (GEIA) in 1991. The purpose of IGAC is to measure, understand, and predict changes in global atmospheric chemistry; the purpose of GEIA is to develop global, 1° resolution, benchmark emissions inventories of a variety of constituents to support atmospheric chemistry models. The modeling community has recognized the significant advantages that accrue to a consensus data effort such as GEIA. E.g., standardized, authoritative source inputs to models reduce uncertainties inherent in model intercomparisons and eliminate duplicative efforts by individual research groups to develop source distributions.

In 1993, GEIA's methane working group, chaired by E. Matthews (GISS), presented methodological recommendations for global gridded inventories of the following natural and anthropogenic methane sources: coal mining and processing, oil and natural gas production, transmission, and distribution, landfills, rice cultivation, wetlands and animals. These recommendations rely heavily on existing and newly developed data sets as starting points, and include specifics about methodologies, uncertainties, and data availability. These methodologies are complemented by similar efforts by the Intergovernmental Panel on Climate Change (IPCC).

As part of this ongoing GISS research, we began our project with Mott Hall Junior High School in the summer of 1996.

Scientific and Project Objectives

The scientific objectives of this research are to understand the global methane cycle, including how its sources and sinks have changed over the last ten years, how they might change in future decades, and what the implications are for climate. Specifically, the student research activity contributes to compiling a current, complete, and internationally-recognized inventory of methane sources and emissions designed as inputs to atmospheric chemistry models and other studies.

Progress to Date

We focus on progress to date since this project is designed to develop inventories of methane emissions for a series of sources, and therefore some of the concepts, techniques, skills, data, and materials developed in the first stage (1996-97) will be used in subsequent stages by other students at Mott Hall and perhaps elsewhere. The focus of the 1996 summer project was on exploring data sources and research materials required for the inventory work. In particular, data and ancillary information were identified and portions of necessary data were organized into a form usable by the students. In particular, H. Augenbraun completed a demonstration product during the summer of 1996 which took the form of a global inventory of a single methane source - wetland rice cultivation. The inventory was accomplished by obtaining information on rice-harvest areas for all rice-producing countries of the world reflecting the GEIA reference year of 1990. Subnational statistics of rice areas were also obtained for the U.S., India, China, and Brazil. Most of these data were obtained through Internet searches. Using geographic information on locations of rice-cultivation from a land-use data set already developed by E. Matthews, and following the default IPCC methodology for estimating methane emission from this source, a global inventory of methane emission from rice cultivation was developed.

The continuation of the project during the 1996-97 school year built on the research carried out at GISS during the summer and extended the summer's demonstration product to encompass an additional methane source. During the 1996-1997 school year, 10 students and the instructor worked on developing an inventory for 1990 contributions of landfills to emission of methane to the atmosphere. They began with North America and the Caribbean where data are prevalent. The IPCC methodologies provide default values for several variables needed in the estimate including per capita refuse production, fraction of refuse placed in landfills, fraction of refuse decomposing anaerobically, methane potential of waste, and level of methane recovery. However, the students needed population statistics in order to estimate the total amount of waste generated, as well as to develop the geographic distribution of methane emission fultimately required by atmospheric chemistry modelers. Working as a team, with one student as a facilitator, each student selected several states/provinces/countries and compiled 1990 population statistics on the following: population of cities >50,000; city latitudes/longitudes; and total, urban and rural populations for states of the US, provinces of Canada, and other countries. Each student contributed his/her population statistics to the effort, and the team carried out the IPCC default calculation of methane emissions from landfills in North America and the Caribbean. The students worked together to produce a report and a science fair poster on their research (The Mott Hall science fair took place on 28 May, 1997). The report/poster describe the scientific background for the study of methane emissions, sources of data, an overview of methane sources, details of the IPCC methodology and how it was implemented, sources of population data, and results of the study. E. Matthews met at Mott Hall with the student team and the faculty member (H. Augenbraun) in November, 1996, to evaluate the students' progress and advise on future directions.

Educational Opportunities and Objectives

The global methane project is a timely and relevant topic that relates directly to the study of global warming. In addition, it confirms the direct relationships between everyday human activities and greenhouse gas emissions. The investigation requires a multidisciplinary approach which includes skills and knowledge in the area of social studies, math, English, writing, science and computers. The students use library and Internet searches to locate needed data. They organize these data on a spreadsheet, and plot their results, using Microsoft Works or Excel. Other educational opportunities include: exposure to varied regional agricultural, nutritional, and energy-use practices; addressing uncertainties inherent in scientific efforts; learning to research, locate, and evaluate data sources; synthesizing large amounts of data into a coherent and concise package; explaining and justifying how and why things were done as they were in the inventories; contributing written and graphic materials to the ICP Web site; preparing written reports, including literature review, background of problem, and results; preparing oral presentations for classmates and others; and creating graphics that communicate major results. The latter three educational opportunities are further developed through participation of the students in the Mott Hall Science Fair.

Summer 1997 Plan

There are three foci for the summer of 1997: 1) prepare and deliver research materials to the ICP Web site; 2) formalize compilation of an evolving library of introductory, background and research materials to support the global warming component of Mott Hall's eighth grade earth science curriculum and the methane project in particular; and 3) undertake a global inventory of another methane source, domestic animals.

1. Contribution to the ICP Web: a) introductory presentation on the global methane cycle in global warming; b) introductory presentation on the methane inventory project; c) summer 1996 faculty report on global distribution of methane emission from rice cultivation for 1990 including; d) global data sets on rice cultivation and associated methane emission developed in the summer 1996 research; e) 1997 Mott Hall student report on methane sources and emissions from landfills in North America and Caribbean; f) data sets of 1990 human populations for North America and the Caribbean collected by the students in 1996/1997 school year including: population of cities >50,000, city latitudes/longitudes, and total, urban and rural populations for states of the US, provinces of Canada, and other countries; g) written report and associated data for methane emissions from animals from summer 1997 project.
2. Introductory and instructional materials for a junior high school earth science curriculum: Many of the Web contributions (above) comprise instructional materials. We will also search out and acquire additional materials that support the global global warming sections of the earth science curriculum and are appropriate, as is, for junior high students. However, we expect that much of the relevant material may be professional literature which will require distillation and and integration. The latter will be accomplished during the summer and during the coming school year.
3. Inventory of animals and associated methane emissions. The student and faculty member of this team will collect 1990 data on animal populations by country, and by political subdivision for large countries. Animals to be included are: dairy and beef cattle, sheep, goats, pigs, water buffalo, and camels. Global methane emission from animals will be calculated using the IPCC default methodology and global 1° resolution data sets of animal densities and associated methane from them will then be developed. We will write up the research as a NASA Technical Memorandum, and for the ICP Web.

Responsibilities: The student team member is responsible for collecting and arranging materials for the Web page, interacting with the ICP personnel responsible for ultimate development of the page, he will also conduct data and literature searches. The faculty member is responsible for data collection for the summer inventory, and for development of curriculum materials. The GISS project scientist is responsible for providing IPCC and other relevant materials, evaluating the methane results vis-a-vis alternative methodologies, and overseeing coordination of the research.

Curriculum 1997-1998

The topic of greenhouse effect and global warming is part of the 8th grade Earth science curriculum at Mott Hall and is taught within the context of the nature of solar energy and its interaction with the earth's atmosphere and surface, and atmospheric chemical processes. Students research the social and economic costs of global warming and methods for reducing greenhouse gas emissions. Another part of the Mott Hall science programs requires each student to conduct an independent science investigation each year. A group of ~10 students will continue the work begun last year on investigating methane emission from landfills. In addition, the methane inventory update provides a data set with which to compare the amount and distribution of emissions for 1985 and 1990. The students can then hypothesize as to future regional and global trends in methane emissions and causes for these changes.