Conceptual Integration

It is important that students bring a certain ragamuffin, barefoot irreverence to their studies; they are not here to worship what is known, but to question it.

—J. Brownowski (1973), The Ascent of Man symbols and systems

This book is as much about the process of learning as it is an interdisciplinary journey through the science and policy of the Earth system. Rather than teaching by the academic method, where information is presented and restated—where facts are decoupled from the processes that uncovered them—this book will introduce an educational environment where learning occurs by asking both factual questions (who, what, when, and where) and process questions (how and why). These questions generate answers that in turn provoke new questions and awaken insights as symbolized by ''the light at the end of the tunnel'' in Plato's Republic.

Individual understanding is reflected by questions that are asked rather than through content that is echoed. With independent initiative, this process of learning by asking questions—the Socratic method—evokes curiosity and activates each of us to formulate, explore, and revise hypotheses about our world.

Developing hypotheses—inferences about how things work—in turn, provides the basis for evaluating and integrating new knowledge in the context of what is already known or understood. The challenge is how to capitalize on this immense base of information, which we already possess by virtue of just living on the Earth and experiencing the world around us every day. The integrated character of the Earth system provides a broadly relevant framework for teaching about the open-ended and dynamic nature of inquiry.

Viewing the Earth as an interconnected environmental system clearly is beyond the domain of any discipline. Moreover, the Earth is a community of nations with myriad interests, ideologies, and histories. If we are to understand how to progress into the 21st century and beyond, then we also must develop the appropriate tools for interpreting interdisciplinary relationships. Examples from Antarctica will be introduced throughout to illustrate the events, entities, and phenomena influencing our Earth system across time and space.

Interdisciplinary approaches involve qualitative and quantitative tools for interpreting relationships. Qualitative tools juxtapose phenomena or fields of information for the purpose of illustrating their general connections. Quantitative tools provide pathways for interpreting dynamic links among the sources and sinks of materials cycling through the Earth system.

Venn diagrams, which describe major spheres and the processes that occur at their intersections, are among the most widely used qualitative tools for describing the integration of diverse phenomena involved with the Earth system. Introduced in the late 1880s by John Venn (1834-1923) for mathematical purposes, these circular diagrams elegantly illustrate the three ways in which information can be related: separate, concentric, or intersecting. Moreover, this symbolic logic provides a powerful method for reducing the complexities of interdisciplinary concepts into concise illustrations that are useful in the classroom outward to society (Fig. 2.1).

For example, on Earth, matter and energy are transferred through the atmosphere, hydrosphere, and biosphere. Venn diagrams can be used to describe relationships between these spheres as with the water-vapor intersection of the atmosphere and hydrosphere. Similarly, carbon dioxide could be described as the intersection of the atmosphere and the biosphere (Eq. 1.1). In all cases, such intersections are elaborated by individual design and can be expanded with additional spheres, especially when the human dimensions are considered.

Why is the Earth considered to be a system?

Models that represent the dynamic relationships between connected reservoirs also can be used for quantifying relationships. An illustration would be two containers of water that are connected by two pipes, one with a valve that controls the outflow and another with a pump that recycles the water. If the rates of outflow and recycling are equal, then water levels in the containers will remain unchanged. If the outflow exceeds the recycling, one of the containers eventually will become empty while the other overflows. The principal advantage of such quantitative models is in estimating actual relationships between reservoirs and their responses to changes in the system.

In a much more elaborate manner, the Earth system also can be modeled as interconnected reservoirs. Water, for example, is cycled between continents through the atmosphere, across lakes, streams, and rivers into the ocean, back into the

FIGURE 2.1 ''Venn diagrams''identify the three types of relationships—separate, concentric, and intersecting—that can exist among events, entities, or phenomena. Different perspectives on the relationships between humans and nature are illustrated to show what can be learned by framing questions through Venn diagrams. Such ''thought questions,'' which are identified throughout this book, provide open-ended tools for interpreting the integrated dynamics of the Earth system and how science is merging into the policies of our society.

FIGURE 2.1 ''Venn diagrams''identify the three types of relationships—separate, concentric, and intersecting—that can exist among events, entities, or phenomena. Different perspectives on the relationships between humans and nature are illustrated to show what can be learned by framing questions through Venn diagrams. Such ''thought questions,'' which are identified throughout this book, provide open-ended tools for interpreting the integrated dynamics of the Earth system and how science is merging into the policies of our society.

atmosphere, and out into masses of ice around the planet. Water volumes in these reservoirs are controlled by evaporation and precipitation along with melting and freezing, as well as by runoff and even sublimation (where water goes directly from the solid to the gas phase). This hydrological system, in turn, is influenced by temperature variations associated with the Earth's weather and climate.

Weather and climate patterns are further influenced by factors that are internal to the Earth system (such as the relative production of greenhouse gases, especially water vapor) as well as external (such as the meteorite that crashed into the Earth and caused the extinction of the dinosaurs 65 million years ago). There also are vital Earth-Sun dynamics that cycle daily through sunrises and sunsets as well as across millennia with the advance and retreat of ice masses across the planet.

The tremendous challenge of characterizing connections among reservoirs in the Earth system—let alone understanding their dynamics—was heralded by the

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