Unit 1.3: Systems Models

Introduction

The term "Earth system science" is typically used to describe the science (especially quantitative modeling) of the interactions between the atmosphere, hydrosphere and cryosphere, and biosphere - the addition of lithosphere to that list provides all of the main generalized components ("spheres") of the Critical Zone. In this lesson, you will consider basic concepts of system science, which will be applied later in the semester to more in-depth systems. In this unit, you will: thinking of the Critical Zone as a complex system, you will engage in developing a qualitative systems model graphic of the Critical Zone. In this unit, you will:

• describe some of the prominent human interactions and impacts with the various components ("spheres") of the Critical Zone
• define the term "system" as it pertains to the natural world, and describe the difference between quantitative and qualitative system modeling
• design a qualitative Critical Zone system model
• explain how (and when) humans have altered global erosion rates
• recognize some of the consequences of human domination of ecosystems
• discuss how human-induced climate change is expected to alter the hydrologic cycle
• describe what global-scale, human-induced changes can be observed in soils, the role of agriculture in these changes, and some of the consequences of changes to our soils
• formulate and evaluate any adaptive actions humanity can take to lessen negative impacts to the Critical Zone and soils.

Unit 1.3: Systems Models

• Everyone should read the following:
• Brantley, S. L., Goldhaber, M. B., & Ragnarsdottir, K. V. (2007). Crossing disciplines and scales to understand the critical zone. Elements, 3(5), 307–14. Focus on how the Critical Zone acts like a system. (Primary link is at: Elements Magazine). Alternative source: http://geomorphology.sese.asu.edu/Papers/Brantley_Elements_07.pdf
• Mann, C. (2008). Our Good Earth. National Geographic, 214(3), 80-106. Notice how excessive and adaptive actions by human society can lead to soil compaction, erosion, and loss of nutrients and organic matter. This article provides some good general information to consider regarding what human actions might be included in the Critical Zone system model to be assigned at the end of this class. (Link may require a FREE registration on the NGM page; Note: this is a link to their NEW beta site so may only be temporary)
• Your group will read one of the following five articles and be prepared to present a 5-minute synopsis of their reading focused on key issues associated with human interaction and impact in their group's "sphere" of the Critical Zone.Other questions the groups should address or be ready to discuss include:
• What is(are) the main idea of the paper(s).
• What research techniques were used?
• What kinds of models or assumptions were applied to this research?
1. Atmosphere and hydrosphere (climate and hydrology):
• IPCC, 2008, Climate Change and Water (7 Mb, slow load)
• Read the executive summary and browse the rest of this important report from the Intergovernmental Panel on Climate Change.
2. Lithosphere and erosion:
• Wilkinson, B. H. (2005). Humans as geologic agents; a deep-time perspective. Geology, 33(3), 161–4. (full PDF requires subscription to Geology)
• Montgomery, D. R. (2007). Is agriculture eroding civilization's foundation? GSA Today, 17(10), 4–9 . doi: 10.1130/GSAT01710A.1.
3. Biosphere:
• Vitousek, P. M., Mooney, H. A., Lubchenco, J., & Melillo, J. M. (1997). Human domination of Earth's ecosystems. Science, 277(5325), 494–9.
4. Soil:
• Richter, D. D. J. Humanity's Transformation of Earth's Soil: Pedology's New Frontier. Soil Science, 172(12), 957–67. (Full PDF requires a subscription)
5. Soils—The Final Frontier"
• Sugden, A., Stone, R., & Ash, C. (2004). Ecology in the Underworld. Science, 304(5677), 1613–1615. See also the interactive version of the map from that article.
• Kaiser, J. (2004). Wounding Earth's Fragile Skin. Science, 304(5677), 1616–1618.
• Stokstad, E. (2004). Defrosting the Carbon Freezer of the North. Science, 304(5677), 1618–1620.
• McNeill, J. R., & Winiwarter, V. (2004). Breaking the Sod: Humankind, History, and Soil. Science, 304(5677), 1627–1629.

Group Reporting

• Each group will take five minutes to report on an article assigned to them as the pre-class homework. This will lead into a class discussion examining the Critical Zone as a system.

Lecture

• Description of systems modeling and the importance and relation to the Critical Zone.

• You should produce a simple Critical Zone system diagram. Due next class.

Additional Resources

• Brantley, S. L., Goldhaber, M. B., & Ragnarsdottir, K. V. (2007). Crossing disciplines and scales to understand the critical zone. Elements, 3(5), 307–14.
• Mann, C. (2008). Our Good Earth. National Geographic, 214(3), 80–106.