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 • Earth system science is a holisitic approach to studying the Earth as a whole system of many interacting parts – Oceans – Atmosphere – Continents – Lakes and rivers
-Soils -Plants -Animals -Rocks
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
Earth System Science
Outline • • • • •
Earth System Science Systems Earth System Reservoirs Dynamic Interactions Among Reservoirs 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 Earth’s 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 Earth’s 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 • • • • •
Earth System Science Systems Earth System Reservoirs Dynamic Interactions Among Reservoirs How Science Works
Earth System Reservoirs Geosphere
Biosphere
Hydrosphere
Atmosphere
Anthroposphere
Earth System Reservoirs • The place where Earth’s 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
Earth System Reservoirs 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 Earth’s surface
Earth System Reservoirs • The Hydrosphere – Earth’s 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
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
Earth System Reservoirs • The Biosphere – Earth’s organisms and matter that has not yet decomposed – The biosphere greatly affects every other of Earth’s systems • Photosynthesis • Oxygen as a highly reactive gas
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
Outline • • • • •
Earth System Science Systems Earth System Reservoirs Dynamic Interactions Among Reservoirs 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 system’s 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)
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
Dynamic Interactions Among Reservoirs • • • • •
Hydrologic Cycle Energy Cycle Rock Cycle Tectonic Cycle Biogeochemical Cycles
Dynamic Interactions Among Reservoirs The Energy Cycle
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 Scycles). • Scientists have coined a term to describe changes produced in the Earth system as a result of human activities: global change
Dynamic Interactions Among Reservoirs
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Earth System Science Systems Earth System Reservoirs Dynamic Interactions Among Reservoirs 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 nonscientists 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 can’t 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:
“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.”
“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).
"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.
