2.7 Using Systems Theory to Understand Physical Geography

Read the Textbook

Systems Organization in Geosystems (page 14)

The following image (from Figure 1.11 on page 19 of the text) illustrates how an eruption may influence many processes in the system that can best be understood from a systems perspective.

global impacts of mount pinatubo's eruption, including aerosol cloud, atmospheric reflectivity, reduced sunlight and increase of diffuse sunlight — **Figure 1.11. Global impacts of Mount Pinatubo’s eruption.** The 1991 Mount Pinatubo eruption affected the Earth–atmosphere system on a global scale. As you read *Geosystems*, you will find references to this eruption in many chapters. A summary of the impacts is in Chapter 13.
Christopherson, R.W., Birkeland, G. H., Byrne, M., Giles, P. T. (2016). *Geosystems: An Introduction to Physical Geography*, Fourth Canadian Edition. Toronto, Ontario: Pearson Canada. View full-size image.

This schematic illustrates the global impact of the 1991 Mount Pinatubo eruption in the Philippines. The aerosols were responsible for intense sunsets, changes the albedo of the planet, changes in the Northern Hemisphere temperature, and the quality of sunlight which had an effect on photosynthesis.

The following illustration, which we saw earlier (Geosystems in Action 1: Exploring Earth Systems, page 16) shows how this type of thinking can reverberate through the components of the Planet Earth.

the four spheres of earth systems: atmosphere, hydrosphere, lithosphere and biosphere — **Geosystems in Action 1: Exploring Earth Systems.** Earth is often described as being made up of four “spheres”—the atmosphere, hydrosphere, lithosphere, and biosphere.
Christopherson, R.W., Birkeland, G. H., Byrne, M., Giles, P. T. (2016). *Geosystems: An Introduction to Physical Geography*, Fourth Canadian Edition. Toronto, Ontario: Pearson Canada. View full-size image.

the atmosphere, hydrosphere, lithosphere and biosphere as a venn diagram with biosphere in the center — **The Atmosphere, Hydrosphere, Lithosphere and Biosphere are all joined and affect each other.**
Christopherson, R.W., Birkeland, G. H., Byrne, M., Giles, P. T. (2016). *Geosystems: An Introduction to Physical Geography*, Fourth Canadian Edition. Toronto, Ontario: Pearson Canada.

The Atmosphere, Hydrosphere and Lithosphere are overlapping circles on the Venn Diagrams to the right, and the Biosphere joins all of them in one way or another. We will be highlighting the first three and using examples of their linkages to the biosphere throughout this course. The objective is for you to understand the processes that link these by the end of the course and understand how they change through time, and how that change can affect other planetary processes.

energy-atmosphere systems with inputs, actions, outputs and the human-earth relation — **Atmosphere**
© University of Waterloo. View full-size image.

water, weather and climate (hydrosphere) systems with inputs, actions, outputs and the human-earth relation — **Hydrosphere**
© University of Waterloo. View full-size image.

earth-atmosphere (lithosphere) systems with inputs, actions, outputs and the human-earth relation — **Lithosphere**
© University of Waterloo. View full-size image.

We will start with Solar Energy which is the primary energy source driving processes on the planet. This energy drives the hydrological cycle and powers the formation of clouds and weather events as well as the carbon and oxygen cycles via photosynthesis and respiration. The water flowing downslope carves the topography of the surface, and the surface topography is renewed by the energy from within the Earth driving plate tectonics. In the following modules we examine each in turn and highlight the linkages that are explained by understanding the processes.