Understanding the Earth as a System
As noted in the National Science Education Standards, "The natural and designed world is complex; it is too large and complicated to investigate and comprehend all at once. Scientists and students learn to define small portions for the convenience of investigation. The units of investigations can be referred to as 'systems'. A system is an organized group of related objects or components that form a whole. Systems can consist, for example, of organisms, machines, fundamental particles, galaxies, ideas, and numbers. Systems have boundaries, components, resources, flow and feedback."
Systems thinking in science education also helps to organize science content into a structured body of knowledge that makes more sense to novice students who can be easily turned off by scientific content because it often appears as a jumble of disconnected facts.
Watch the “Earth as a System” video from PBS LearningMedia and think about some of the interactions between the air, land, water, and life.
One of the most important changes in our approach to the Earth sciences is the integrating idea of the Earth as a system. In other words, when it comes to phenomena that take place in our natural systems, everything is connected to everything else. The idea of the Earth as a system is one of the reasons that scientific investigations are becoming more and more interdisciplinary. With systems thinking as a fundamental way of looking at the world around us, we have an inquiry structure that predisposes scientists to look at change in one sphere, such as the atmosphere, and then see if there are impacts of that change in another sphere, such as the hydrosphere or lithosphere.
Now watch the video "There's No Place Like Earth" and consider what it means to look at Earth as a system.
Systems are identified by several components: inputs, outputs, and feedbacks. Look at the following diagram and make note of these components in the Arctic climate system over time.
This diagram shows the Arctic climate system over time, showing positive feedbacks. Note that the ice-albedo feedback increases melting permafrost, and melting permafrost adds more greenhouse gases to the atmosphere, which exacerbates the melting of ice and loss of albedo.
Consider reviewing the "Arctic Climate System" video again from the Explore section, to once again compare global systems to smaller systems "closer to home."
Now that you have ascertained some of the positive feedbacks that take place at the Earth's poles, think again about the Earth as a system. How does the presence or absence of ice at the poles impact the atmosphere and ocean, and ultimately, the rest of the planet? The answers to these questions are answered by Dr. Tom Wagner, Cryosphere Scientist at NASA in the video "NASA Earth Climate Checkup: Operation Ice Bridge." Some of the technological tools used to map ice are also described.
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