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Topic(s):

Climate

 

Scenario:

Methane: The other greenhouse gas

At the moment, the atmosphere contains much more carbon dioxide than it does methane. Yet, methane is considered a potent greenhouse gas because it is at least 10 times more effective than carbon dioxide at trapping heat in the atmosphere.

A September 2006 study in the journal Nature reported about the bubbling of methane hydrates, also called methane clathrates, in Siberian thaw lakes. A thaw lake is a body of water that forms from thawing permafrost -- soil and rock that had remained below 0ºC for at least two consecutive years. Thaw lakes exist throughout Siberia, Alaska and arctic Canada.

Until recently, the methane in these methane hydrates -- ice-like substances in which molecules of methane are trapped -- was thought to be solidly locked beneath the ground. In fact, scientists at Lawrence Livermore National Laboratories and the U.S. Geological Survey (USGS) have shown how methane hydrates can be stable at pressures as low as 1 atmosphere (the standard air pressure at sea level) if the temperature is low enough. Methane hydrates are also found in deep beds beneath the ocean, where the pressure is high enough and temperatures cold enough to keep them stable.

The Nature article, however, discusses how the Siberian thaw lakes may be emitting into the atmosphere as much as five times the amount of methane than previously thought. Estimates are that about 10,000 gigatons of carbon are contained in methane hydrates worldwide. This compares to the 700 gigatons of carbon now present in Earth's atmosphere. Geologic evidence indicates the rate of release into the atmosphere of this methane increases during periods of warming. So not only does methane contribute to greenhouse warming, but warming itself can result in the release of additional methane.

Ice core samples taken from Vostok in Antarctica show a strong correlation between methane concentrations and air temperature over a 420,000-year record. They correlate well even with the cooling associated with the Younger Dryas event that occurred 12,500 years ago (see image from NASA on the right). Other ice core records that go back as far as 110,000 years from Greenland and 750,000 years from Antarctica show that concentration of carbon dioxide and methane can be correlated with temperatures.

There is some evidence that massive release of methane over geologic time, going back at least 250 million years ago, has had a profound influence on global environmental change, affecting not only Earth's climate, but possibly the extinction of many species. It probably played a role as Earth came out of the period of "snowball Earth" about 635 million years ago. Indirect evidence indicates the entire Earth was glaciated during this period.

According to the USGS, the methane now contained in methane hydrates is estimated to contain twice the amount of carbon found in fossil fuel reserves.

 

Task:

Recent research has shown that some methane hydrates have become unstable. This could add methane, a greenhouse gas, to the atmosphere. The current focus in the global climate change community has been on the effects of carbon dioxide in the atmosphere. Your team has been asked to assess the effects methane can have on Earth's systems and to make recommendations on how to handle the methane hydrates.

 

Date: 4/14/2009

Scenario Images:

Methane and Temperature record from Vostok
Ice core samples taken from Vostok in Antarctica show a strong correlation between methane concentrations and air temperature over a 420,000 year record. Larger image. Image: Courtesy NASA GISS



Atmospheric methane concentration trends
In the modern period seen in the higher accumulation core at Law Dome (Antarctica), the relatively stable pre-industrial value of 700 ppb is shown to have increased to 1750 ppb today. Larger image. Image: Courtesy NASA GISS



Resources:

 

A Global Inventory of Natural Gas Hydrate Occurrence (Cycle A)
Describes where all natural gas (including methane) hydrates are located worldwide.

 

AN ALTERNATE SCENARIO FOR CLIMATE CHANGE (Cycle A)
This GSFC article discusses the possible role of methane in climate change.

 

Carbon dioxide, methane rise sharply in 2007 (Cycle A)
Describes the increases in carbon dioxide and methane that occurred in 2007.

 

What is a feedback loop? (Cycle A)
Explains what a feedback loop is and why feedback loops are important in trying to determine climate trends.

 

Global Warming Feedback Loop Caused by Methane, Scientists Say (Cycle B)
Explores how warming and methane release from hydrates are related in a feedback loop.

 

Large Methane Release Could Cause Abrupt Climate Change As Happened 635 Million Years Ago (Cycle B)
This article discusses an apparent relationship between abrupt climate change and methane release.

 

Methane Bubbling From Arctic Lakes, Now And At End Of Last Ice Age (Cycle B)
Discusses how methane bubbling from arctic lakes contributed to a methane spike as Earth came out of the last Ice Age.

 

Methane burps disproved? (Cycle B)
This website discusses the evidence that is contrary to the methane gun hypothesis.

 

Methane Hydrate and Abrupt Climate Change (Cycle B)
Looks at the possible role methane hydrate may have in abrupt climate change.

 

Methane Hydrates and Climate Change: The Clathrate Gun Hypothesis (Cycle B)
Discusses the role of the recharging during cold clomates and discharging during warm climates of nethane clathrates.

 

Methane releases from arctic shelf may be much larger and faster than anticipated (Cycle B)
Describes how permafrost along the east Siberia arctic shelf is leaking methane into the atmosphere.

 

Ocean Burps and Climate Change? (Cycle B)
Information on the effect of methane release during the Paleocene/Eocene Thermal Maximum.

 

The National Methane Hydrates R&D Program (Cycle B)
Discusses methane hydrates in Arctic regions.

 

Ocean Explorer/Explorations (Cycle C)
Describes under sea methane as a possible resource and a frozen hazard.

 

The National Methane Hydrates R&D Program All About Hydrates - Hydrates and Deep Marine Life (Cycle C)
Describes how methane hydrates are related to deep marine life in the Gulf of Mexico.

 

Sample Investigations:

 

Journey to Mars: Out of Thin Air (Cycle A)
This experiment uses electrolysis to produce oxygen and hydrogen from water.
"Students also learn that in the proposed Mars chemical plant, the Sabatier reaction combines carbon dioxide with hydrogen to produce methane (which forms the basis for methanol rocket fuel) and water. After water (H2O) is obtained, it can be separated into its two components, hydrogen and oxygen. Similarly, scientists have proposed that oxygen can be obtained from ice on the moon. The oxygen would be stored as rocket propellant, and the hydrogen recycled back into the chemical plant to make more methane and water. The methanol would also be used by Mars rovers as fuel. "
Difficulty: beginner

 

The Big Burp: A bad day for the Paleocene (Cycle A)
Contains exercises on methane hydrates and methanogenic bacteria using the Blake Ridge east of Charlston SC as an example.
Difficulty: beginner

 

Human Activity and Climate Change (Cycle B)
"In this activity, students will examine graphs of greenhouse gas (GHG) emissions and their increases associated with human activity. They will focus on carbon dioxide, methane, nitrous oxide, chlorofluorocarbons (CFCs), and ozone. They will calculate some personal contributions to emissions. When students finish this activity, they will be able to identify sources of the major greenhouse gases and identify the current trends in atmospheric concentrations. Students also will be able to calculate greenhouse gas emissions on personal and larger scales. The teacher's guide contains detailed background material, learning goals, alignment to national standards, grade level/time, details on materials and preparation, procedure, assessment ideas, and modifications for alternative learners."
Difficulty: intermediate

 

The Big Burp: Where's the Proof? (Cycle B)
Explores the potential role of methane in global warming
Difficulty: intermediate

 

This life stinks (Cycle C)
Explores methane-based chemo-synthetic process
Difficulty: advanced

 

What's the big deal? (Cycle C)
Significance of methane hydrates.
Difficulty: intermediate

 

 

Standards:

  • Science
    National Science Education Standards - Science Content Standards http://www.nap.edu/readingroom/books/nses/html/overview.html#content The science content standards outline what students should know, understand, and be able to do in the natural sciences over the course of K-12 education.
    • GRADES 9-12 CONTENT STANDARDS
      • Science as Inquiry (Std A)
        • Abilities necessary to do scientific inquiry
        • Understanding about scientific inquiry
      • Physical Science (Std B)
        • Structure and properties of matter
        • Conservation of energy and increase in disorder
        • Interactions of energy and matter
      • Life Science (Std C)
        • Biological evolution
      • Earth and Space Science (Std D)
        • Energy in the earth system
        • Origin and evolution of the earth system
      • Science and Technology (Std E)
        • Abilities of technological design
        • Understanding about science and technology
      • Science in Personal and Social Perspectives (Std F)
        • Natural resources
        • Environmental quality
        • Natural and human-induced hazards
        • Science and technology in local, national, and global challenges
  • Geography
    Geography for Life: National Geography Standards, 1994
    • THE WORLD IN SPATIAL TERMS
      Geography studies the relationships between people, places, and environments by mapping information about them into a spatial context. The geographically informed person knows and understands:
      • How to analyze the spatial organization of people, places, and environments on Earth’s surface
    • PLACES AND REGIONS
      The identities and lives of individuals and people are rooted in particular places and in those human constructs called regions. The geographically informed person knows and understands:
      • The physical and human characteristics of places
    • PHYSICAL SYSTEMS
      Physical processes shape Earth’s surface and interact with plant and animal life to create, sustain, and modify ecosystems. The geographically informed person knows and understands:
      • The characteristics and spatial distribution of ecosystems on Earth’s surface
    • ENVIRONMENT AND SOCIETY
      The physical environment is modified by human activities, largely as a consequence of the ways in which human societies value and use Earth’s natural resources, and human activities are also influenced by Earth’s physical features and processes. The geographically informed person knows and understands:
      • How human actions modify the physical environment
      • How physical systems affect human systems
    • THE USES OF GEOGRAPHY
      Knowledge of geography enables people to develop an understanding of the relationships between people, places, and environments over time — that is, of Earth as it was, is, and might be. The geographically informed person knows and understands:
      • How to apply geography to interpret the past
      • How to apply geography to interpret the present and plan for the future
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