EDUCATION: GLOBAL METHANE INVENTORY

Lessons

The following lessons, to be carried out in the classroom over two to three class periods, introduce the greenhouse effect and the methane cycle. The lessons exercise such skills as data analysis and mathematical reasoning, described in greater detail below. The lessons can stand alone or can be used as preliminary to the research projects, listed on the Research Projects section of the web site.

Topic 1: The Greenhouse Effect

The Earth's surface spheres (atmosphere, hydrosphere, lithosphere, biosphere) interact and behave much like a living community. The interaction of these spheres with solar energy and each other results in changing conditions which we refer to as weather and climate. Before reaching the Earth's surface, solar radiation passes through clouds and atmosphere, which reflect, scatter, absorb, and transmit various amounts of energy. The Earth's surface reflects some of the incoming solar radiation and absorbs the remainder. As the surface absorbs the energy, it heats and radiates the energy back into space.

When the rates of absorption and radiation are equal (radiative balance) the Earth's temperature is stable. If the atmosphere did not exist, the Earth's surface would reach radiative balance at 33°C (60°F) below its present balance temperature. However, some gases in the atmosphere absorb some of the energy radiated from the surface. They heat and re-radiate energy back to the surface. In this way, the atmosphere maintains a higher surface temperature than the Earth would have without an atmosphere. This process is called the greenhouse effect.

There is one lesson for this topic:

Lesson 1-1: The Role of the Atmosphere and Greenhouse Effect in Determining the Surface Temperature of the Earth

This lesson investigate the nature of the natural greenhouse effect and its effect on making the Earth a habitable planet. The lesson uses interactive software available on the ICP website. The skills taught by the lesson are the following:

• Use of technology
• Data interpretation and analysis
• Mathematical reasoning

Topic 2: The Methane Cycle

Global average change in atmospheric methane concentrations in parts per billion.

Methane (CH₄) is a potent greenhouse gas about 30 times more efficient at trapping heat in the Earth's atmosphere than carbon dioxide (CO₂) on a molecule-for-molecule basis. Although a great deal of scientific research and press coverage is devoted to CO₂, the growth of methane has contributed about 20% to the total radiative forcing over the last century. However, measurements of atmospheric concentrations that began in 1983 show that methane levels have continued to increase but the rate of growth slowed down during the 1990s.

Why has the growth rate in atmospheric concentration of methane slowed down? Possible explanations are that sources (inputs into the atmosphere) have stabilized or declined, and/or sinks (removals from the atmosphere) have increased.

By the time you have completed topic 2, you will have:

• Identified sources and sinks of atmospheric methane.
• Examined the trend in emissions from sources and removal by sinks over the past 20 years.
• Used your data and analysis to propose a possible answer to the problem.

In order for you to investigate the problem, several questions need to be answered: What are the sources and sinks of methane? What information about each do I need to know? What data do I need? Once you have the answers to these questions, how will you organize your data so you can report it to the class and then use it to solve the problem?

This topic has two lessons:

Lesson 2-1: Trends in Methane Emissions and Sinks

Student teams design an experiment to investigate the following question: Why is the rate of increase in atmospheric concentrations of methane slowing down? The skills taught by the lesson include:

• Experimental design
• Data organization
• Graphing skills

Lesson 2-2: Net Gain or Loss of Atmospheric Methane

Students use their data from the "Trends" lesson above, along with additional data, to obtain a net emissions time series which they compare to a time series of atmospheric concentrations. The skills taught are the following:

• Data organization and its relation to graphing
• Graph analysis

Lesson 2-3: Who Contributes the Most Methane? Per Capita Methane Emissions in the NY Metro Area

Students use data from NASA/ICP climate research to calculate population densities and per capita methane emissions from animals and landfills for New York and four neighboring states. The skills taught are the following:

• Data organization

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