What is the focus of this module? In this module students examine humankind's impact on the global environment, identify possible sources of global warming, evaluate conflicting evidence, and recommend a course of action.

What are some interrelated teaching opportunities? While the "Earth on Fire" module offers students a global perspective on the issues and causes surrounding global warming, it also stresses mathematical modeling and uncertainty, and explores issues of economics, politics, world resources, and social justice as they relate to the emission of greenhouse gasses.

What is the compelling problem that students will face in this module? Is the cumulative weight of human activities changing the earth's climate and undermining the environment? In order to make an informed recommendation, students must collect data in the form of measurements taken through satellite imagery. Students graph and analyze the data, then investigate how to reduce emissions fairly for all nations without damaging the world economy.

What topics and issues will students encounter as they work through this module? The first part of the module asks students to calculate the amount of carbon dioxide emitted by the fires in Yellowstone National Park. This tasks leads to topics such as greenhouse gases, solar output, and the earth's orbit.

What is the role of remote sensing in this module? The remote-sensing activities give your students the data they need in order to evaluate the significance of proposed sources of CO₂ in accounting for the CO₂ concentration data in the Mauna Loa graph. These sources of CO₂ include industrial pollution, volcanic eruptions, seasonal changes in vegetation, and biomass burning (from both natural and human causes).

The first remote-sensing activity in this module involves monitoring the release of carbon dioxide from a specific event--the Yellowstone fires. Remote sensing is used to analyze burned areas, determine how much biomass was converted into CO₂, determine how much biomass is created during a growing season and hence how much CO₂ is removed from the atmosphere, and to illustrate and emphasize points made in the text. The remaining activities examine the increase of atmospheric CO₂:

"Seasonal Vegetation Changes?" asks whether global seasonal changes in vegetation can account for the observed changes in atmospheric CO₂ concentration.

"Fossil Fuel Burning?" has students calculate the amount of CO₂ released to the atmosphere in parts per million by fossil fuel burning and compare it to the actual increase in atmospheric CO₂.

"Fit CO₂ Curve?" asks students to curve-fit a graph. This simple modeling activity develops a curve-fitting equation, which duplicates the data curve of the Mauna Loa CO₂ plot. Once this equation is developed, predicting a future point on the curve is as easy as plugging in the new x-value and calculating the new y-value. 

"Balance the Carbon Cycle?" uses the data in the carbon cycle diagram to have students balance the carbon cycle. Since the carbon cycle is a closed system, all carbon must be accounted for; none can disappear. Students are asked to consider whether sinks are growing or shrinking. For instance, from the Mauna Loa CO₂ spreadsheet data, they can calculate the increase in atmospheric carbon with a high degree of certainty. 

"Uncertainty in CO₂ Data?" asks students to compare measurement error with uncertainty. Every measurement has some uncertainty associated with it due to the imprecision of the measuring instrument. To minimize uncertainty, scientists measure several times. Doing so also helps to eliminate true errors made when taking or reading measurements.

Preparation Checklist--have you thought of everything?

Resources for this module
Yellowstone Burning (video)

Eyes in the Sky (video)

Note: The source of the 160,000-year Temperature and CO₂ History graph is Channel Pi Video Productions. Look under Greenhouse Effect for the Temperature vs. Carbon Dioxide (160,000 ybp) graph and aspects of global climate change from the University of Maryland. For more information regarding the source of the data for the 60,000-year Temperature and CO₂ History graph, you may want to see the "Historical carbon dioxide record from the Vostok ice core." After you read the abstract, you may want to click on Digital Data at the top of the page to see the actual data source for the graph.