Exploring the Global Carbon Budget

Dan Maxbauer, Carleton College

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Initial Publication Date: December 9, 2022


How much carbon is emitted each year due to human activity? How does that number compare to rates of exchange between carbon cycle reservoirs? Where do our carbon emissions go? In this module, students will explore global carbon budget data to 1) determine the rate of change in carbon emissions, 2) explore changes in carbon cycle sinks over time to investigate where carbon emissions end up, and 3) determine what kinds of rates of change are needed to reduce carbon emissions to zero in the future.

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Learning Goals

Following successful completion of this module, students will be able to:

  1. Create appropriate visualizations of global carbon budget data.
  2. Use data to support their understanding or interpretation of global carbon budgets over time.
  3. Demonstrate an ability to address questions about future carbon budget projections with regards to available data.

Context for Use

This module is designed to be completed within one 3-4 hour lab period or split across 2-3 lecture class period depending on class length. The original module was developed for a mid-level geology and environmental studies course with 18-20 junior-senior level students. During one 70 minute lecture period, the activity was introduced (including software) and students worked through Activity A. In a subsequent 70 minute lecture, students worked to complete Activities B + C. The following class period (a 60 minute lecture) provided an opportunity for students sharing out in response to their work on Activity C, leading into a class discussion.

How Instructors Have Used This Module

Using Project EDDIE modules in Carbon and Climate
Dan Maxbauer, Carleton College
The Exploring the Global Carbon Budget module is helpful for student exploration for how carbon emissions interact with the natural exchange of carbon in global carbon cycle. The combination of data visualization and active learning helps students grasp both the magnitude and rates of carbon exchange each year.

Description and Teaching Materials

Quick overview of the activities in this module

See the teaching materials files, provided below, for a step-by-step description for carrying out this module. A student handout, describing Activities A, B, and C, and instructor answer key are also provided.

  • Activity A: Students create a graph of global carbon budget data from 1850-2021, answer a few questions related to interpreting their graph, and write a one paragraph summary of their understanding of global carbon budget data.
  • Activity B: Students walk through a guided breakdown of the major components to fossil carbon emissions by source.  Questions guide students to address which sources of fossil carbon have increased and decreased, and by how much, over time. Students then work through a less-structured breakdown of which carbon cycle sinks (reservoirs) are taking up carbon each year, including an evaluation of how those sinks have changed over time. This activity will include examples for how to calculate the percentage of fossil carbon emissions are taken up by each sink each year...including plots of this percentage over time. 
  • Activity C: This part of the module is the most flexible. Students will use this activity to explore what future global carbon budgets might look like in the year 2050. What of combination in fossil carbon emission reductions are needed each year to reach net zero emissions? How much of a reasonable offset can carbon sinks have if their ability to take up carbon changes by a certain percentage each year? Based on their answers to the question of future scenarios, students should write a set of questions that might arise from their back of the envelope style calculations. For example, how reasonable is it for the ocean sink to change by a given percent each year? What are the associated impacts of changes a carbon sinks capacity? I imagine there could be many questions that arise from this exercise. Student answers from Activity C will be shared with the class during a subsequent lecture, or could be collected online, and used to guide further class discussion. 

Workflow of this module:

  1. Assign any pre-class readings
  2. Give students their handout when they arrive to class
  3. Instructor gives brief PowerPoint presentation with background material. Discussion of the readings can be integrated into this presentation or done before.
  4. Students can then work through the module activities.

Teaching Materials

Teaching Notes and Tips

See Instructor PowerPoint linked above for a pre-activity lecture guide. Additionally, a document with teaching notes and tips for instructors (Microsoft Word 2007 (.docx) 16kB Nov7 22) is available.


Students will create graphs and visualizations within each activity in this module (learning goal 1). In their written responses, students will use data they evaluate to answer and demonstrate their understanding of carbon budgets (learning goal 2). During in class discussion and in their written responses, students will apply their understanding of the global carbon budget data to explore future scenarios.

References and Resources