Download - Chapter 1 - The Earth System.pdf
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The Earth System The Blue Planet: Chapter 1
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Outline
Earth System Science
Systems
Earth System Reservoirs
Dynamic Interactions Among Reservoirs
How Science Works
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Earth System Science
Earth system science is a holisitic approach to studying the Earth as a whole system of many interacting parts
Oceans -Soils
Atmosphere -Plants
Continents -Animals
Lakes and rivers -Rocks
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Earth System Science
Requires observations of Earth at various scales (spatial + temporal)
The quintessential tool for making these observations is remote sensing with satellites
Geographic Information Systems (GIS) provide ways for scientists to store and analyze vast amounts of data
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Earth System Science
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Outline
Earth System Science
Systems
Earth System Reservoirs
Dynamic Interactions Among Reservoirs
How Science Works
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Systems
A system = any portion of the universe that can be isolated for the purpose of
observing and measuring changes
What is an isolated system?
What is a closed system?
What is an open system?
By observing and measuring changes, systems can be used to study complex
problems
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Systems
The mountain-river-lake system can be viewed in whole or divided
into smaller subsytems.
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Systems
A model is a representation of something (an artificial system),
typically a simplification of a complex
original at a more manageable scale
We can build models of objects and processes, which can represent some
of Earths systems
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Systems
Physical model Graphical model
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Systems A box model is a simple graphical representation of a system the arrows depict processes (in this case evaporation and
precipitation).
The places where energy or matter is stored = reservoirs
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Systems A box model is a simple graphical
representation of a system
It can show essential features:
The processes + rates by which matter or energy enters and leaves the system
The processes + rates by which matter or energy moves within the system
The amount of matter or energy in the system and its distribution
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Systems A key to understanding the Earth system is to
measure how volumes and exchanges of
materials and energy between Earths reservoirs change over time
The next challenge is to determine why the changes happen, and how quickly (the rate of
change)
If this can be accomplished the model changes from a qualitative model to a quantitative model
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Systems The amount and of energy or matter that is transferred = flux
The places where energy or matter is stored = reservoirs
If flux into a reservoir is > than the flux out, that reservoir is a sink
If the flux into a reservoir is < than the flux out, that reservoir is a source
Length of time energy or matter spends in a reservoir = residence time
If time is so great that matter is isolated for very long periods, it is called sequestration (e.g., water in glacial ice; organic matter into fossil fuels, etc.). Materials that are sequestered are isolated from contact with the rest of the Earth system.
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Systems
Earth comprises four vast reservoirs with continuous flows of energy and
matter among them
Atmosphere
Hydrosphere
Biosphere
Geosphere
As a whole, Earth is essentially a closed system (although subsystems are open
systems).
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Systems
Box model - interacting parts Earth as a closed system
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Systems
Two important implications of Earth being a closed system are
1. Amount of matter in a closed system is fixed and finite (this applies to both resources and waste materials)
2. If changes are made in one part of a closed system, the results eventually will affect other parts of the system (e.g., 1815 eruption of Tambora volcano)
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Outline
Earth System Science
Systems
Earth System Reservoirs
Dynamic Interactions Among Reservoirs
How Science Works
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Earth System Reservoirs
Geosphere Hydrosphere Atmosphere
Biosphere Anthroposphere
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Earth System Reservoirs
The place where Earths four reservoirs interact most intensively is a narrow zone called the life zone
Conditions favorable for life are formed by interactions between the lithosphere, hydrosphere and atmosphere, and modified by the biosphere
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Earth System Reservoirs
Habitable environments on Earth
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Earth System Reservoirs The Geosphere
Is the solid earth
Composed mainly of rock and regolith
Lithosphere (rocks) + pedosphere (soil)
Where energy from outside the Earth system meets energy from within the planet
Energy sources combine and compete to build up and wear down the materials of Earths surface
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Earth System Reservoirs The Hydrosphere
Earths water
Includes oceans, lakes, streams, underground water, and all snow and ice
The perennially frozen parts of the hydrosphere are called the cryosphere
The hydrosphere and atmosphere store, purify, and continually redistribute water
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Earth System Reservoirs
The Atmosphere
Mixture of gases that surrounds Earth
Predominantly N, O2, Ar, CO2, and H2O
Very thin layer that protects life from damaging solar radiation
Reservoir for oxygen and carbon dioxide
Outer boundary of the Earth system
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Earth System Reservoirs
The Biosphere
Earths organisms and matter that has not yet decomposed
The biosphere greatly affects every other of Earths systems
Photosynthesis
Oxygen as a highly reactive gas
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Earth System Reservoirs
The Anthroposphere
The human sphere
People, their interests, and their impacts on the Earth system
The part of the natural system that has been modified by humans
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Outline
Earth System Science
Systems
Earth System Reservoirs
Dynamic Interactions Among Reservoirs
How Science Works
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Dynamic Interactions Among
Reservoirs
Because energy flows freely into and out of Earth sub-systems, all closed and open
systems respond to inputs and, as a result,
have outputs
A special kind of response, feedback, occurs when the output of the system also
serves as an input
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Dynamic Interactions Among Reservoirs -Negative feedback: the systems response is in the opposite direction of initial input (self-regulating in a state of dynamic equilibrium)
-Positive feedback: increase in output leads to a further increase
in output (destabilizing)
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Dynamic Interactions Among
Reservoirs The constant movement of material
(and energy) from one reservoir to another is called a cycle
Natural cycles are not simple, and exist in a state of dynamic equilibrium
There are many important Earth cycles
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Dynamic Interactions Among
Reservoirs
Hydrologic Cycle
Energy Cycle
Rock Cycle
Tectonic Cycle
Biogeochemical Cycles
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Dynamic Interactions Among
Reservoirs The Energy Cycle
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Dynamic Interactions Among
Reservoirs Humans influence or affect natural cycles
Significant changes are now taking place in many Earth reservoirs, as a result, many are
changing in unexpected ways (e.g., C- and S-
cycles).
Scientists have coined a term to describe changes produced in the Earth system as a
result of human activities: global change
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Dynamic Interactions Among
Reservoirs
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Outline
Earth System Science
Systems
Earth System Reservoirs
Dynamic Interactions Among Reservoirs
How Science Works
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How Science Works
Earth system science, like all other forms of science, advances by
application of the scientific method
The scientific method is based on observations and systematic collection
of evidence (data; a key concept is to
distinguish what is data and what is
interpretation)
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How Science Works
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How Science Works
Scientists start with an observation and seek to acquire evidence about it through measurement and experimentation
Scientists try to explain their observations by developing a hypothesis
Once a hypothesis has been examined and found to make successful predictions and withstand numerous tests, it may become a theory
Eventually, a theory or group of theories whose applicability has been decisively demonstrated, may become a law or a principle (e.g., laws of thermodynamics)
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Mount Sharp, Gale Crater (NASA Curiosity Rover)
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How Science Works
The fact that nothing is absolutely certain in nature is not problematic for scientists, but can be difficult for non-scientists to comprehend fully
It is important to understand that uncertainty does not imply a lack of scientific knowledge or understanding
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Theory (unfalsafiable claim) Fact (use only those facts* that do not
contradict the theory) Law (untested, unquestioned conclusion)
*Note that the facts need not support the theory either; they just cant
contradict it. Any evidence or data that contradicts the theory is either ignored
or considered seriously flawed or fabricated.
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Pseudo-science is not falsifiable, its results cannot be
reproduced in a laboratory or verified with empirical
data, and it does not change its beliefs in the face of
contradictory (or lack of) evidence.
On the other hand, the success and credibility of
science is anchored in the willingness of scientists to:
1. Expose their ideas to independent testing and replication by
other scientists. This requires complete and open exchange of
data, procedures, and materials.
2. Abandon or modify accepted conclusions when confronted
with more complete, reliable, precise, or new experimental or
observational data. In this regard, science is a building process:
it EVOLVES! **No scientist believes that theories are absolute
truth: they are always considered tentative ideas that minimize
uncertainty.
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The
American
Geophysical
Union
Mission:
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All basic types of living things, including man, were made by direct creative acts of God during the
Creation Week described in Genesis. Whatever biological changes have occurred since Creation Week have
accomplished only changes within the original created kinds. (read: Organic Evolution by any mechanism
is a hoax).
The great flood described in Genesis, commonly referred to as the Noachian Flood, was an historic event
worldwide in its extent and effect. (read: Physical Evolution by observed Earth processes is a hoax).
The CRS advocates the
concept of special creation
(as opposed to evolution),
both of the universe and of
the earth with its
complexity of living
forms. Membership in the
Society requires
agreement with the CRS
Statement of Belief.
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"There is no theory of evolution. Just a
select group of creatures Chuck Norris has
allowed to live"
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*This is pseudo-science because the facts/data do not dictate the conclusions; rather
the conclusions dictate the facts and the conclusions will (can) never change.