Chapter 1 - The Earth System.pdf

The Earth System The Blue Planet: Chapter 1

Outline

Earth System Science

Systems

Earth System Reservoirs

Dynamic Interactions Among Reservoirs

How Science Works


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


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

Outline


Systems



How Science Works

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

Systems

The mountain-river-lake system can be viewed in whole or divided

into smaller subsytems.

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

Systems

Physical model Graphical model

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

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

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

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.

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).

Systems

Box model - interacting parts Earth as a closed system

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)

Outline


Systems



How Science Works


Geosphere Hydrosphere Atmosphere

Biosphere Anthroposphere


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


Habitable environments on Earth

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

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


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


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


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

Outline


Systems



How Science Works

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

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)


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


Reservoirs

Hydrologic Cycle

Energy Cycle

Rock Cycle

Tectonic Cycle

Biogeochemical Cycles


Reservoirs The Energy Cycle


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


Reservoirs

Outline


Systems



How Science Works

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)

How Science Works

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)

Mount Sharp, Gale Crater (NASA Curiosity Rover)

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

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.

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.

The

American

Geophysical

Union

Mission:

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.

"There is no theory of evolution. Just a

select group of creatures Chuck Norris has

allowed to live"

*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.

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Chapter 1 - The Earth System.pdf