Carbon in the Atmosphere

Introduction

In the atmosphere, carbon exists primarily in the form of carbon dioxide (CO₂) and methane gas (CH₄). In the global carbon cycle, the atmosphere serves as a Grand Central Station, with carbon dioxide moving into and out of the atmosphere through multiple natural exchange points such as plants, animals, soils, sediments and oceans.

Over Earth's history, slow carbon cycles and fast carbon cycles have worked in tandem to stabilize the carbon cycle. However, burning fossil fuels, deforestation and other land use changes are disrupting the carbon cycle by increasing the concentration of carbon dioxide in the atmosphere. This disruption is significant for our climate because carbon dioxide is the most important gas for controlling Earth's atmospheric temperature.

In Part A, you will use an animation, charts, and a short video to learn the basics of greenhouse gas chemistry, including what carbon compounds exist in the atmosphere and their relationship to the greenhouse effect. In Part B, you will use a graph and videos on historical ice core carbon dioxide (CO₂₎data to investigate the relationship between ices ages, interglacial periods and changes in CO₂ levels. In Part C, you will examine more current CO₂and temperature data to reveal the relationship between current trends in global temperatures and atmospheric carbon dioxide levels. Using NOAA's CarbonTracker, you will investigate and compare atmospheric CO₂ time series data sampled from different parts of the world.

After completing this Lab, you should be able to:

• Explain how carbon dioxide and other greenhouse gases absorb infrared radiation and warm the lower atmosphere.
• Explain how scientists use historical ice core CO₂ and temperature data in combination with more current CO₂ and temperature data to reveal the relationship between trends in global temperatures and atmospheric CO₂ levels.

Keeping Track of What You Learn

Throughout these labs, you will find three kinds of questions.

• Checking In questions are intended to keep you engaged and focused on key concepts and to allow you to periodically check if the material is making sense. These questions are often accompanied by hints or answers to let you know if you are on the right track.
• Stop and Think questions are intended to help your teacher assess your understanding of the key concepts and skills you should be learning from the lab activities and readings.
• Discuss questions are intended to get you talking with your neighbor. These questions require you to pull some concepts together or apply your knowledge in a new situation.

Your teacher will let you know which answers you should record and turn in.