This document discusses key concepts in systems science. It defines a system as interconnected parts forming a whole and describes open systems that exchange matter and energy with surroundings and closed systems that do not. Feedback occurs when a system's output becomes its input and can be negative, stabilizing around an average, or positive, driving large changes. Earth system science considers interactions between the atmosphere, hydrosphere, geosphere, and biosphere as well as human impacts. The hydrosphere includes all water, the biosphere all living things, the lithosphere the solid Earth, and the atmosphere the air surrounding Earth.

1. SYSTEMSSCIENCE

2. SYSTEM
• A set of connected, interacting
parts forming a complex whole

3. OPEN SYSTEM
• Able to exchange matter, energy and
information with their surroundings
• Constantly changing though processes
and relative outcomes relatively
constant
• Most common
• Ex: Ecosystems, living organisms, ocean,
etc.

4. CLOSED SYSTEM
• Exchanges energy but not matter with
its surroundings
• Water and Nitrogen cycles are pretty
close to being closed systems
• The Earth is a pretty much a closed
system; receives energy from sun but
does not really exchange matter with
the universe

5. FEEDBACK
• Occurs when the output of the system is
used as an input in that system
• Two types: Negative & Positive

6. NEGATIVE FEEDBACK
• Tend to stabilize a system around a mean/average condition
• Ex: Climate control/HVAC in your house
Increased surface
temperature
Increased ocean
evaporation
Increased cloud cover
More sun reflected
back to space
Decreased surface
temperature
Decreased ocean
evaporation
Decreased cloud
cover
Less sun reflected
back to space

7. POSITIVE FEEDBACK
• Increase a departure from the mean
• Tend to drive large scale changes to the climate and environment
Increased surface
temperature
Increased melting fo
permafrost
Increased surface
temperature
Increased ice melting
Decreased albedo
(reflected sun)
More heat retainedRelease of methane
Enhanced greenhouse
effect

8. EARTH SYSTEMS SCIENCE
• Considers interactions between the
Earth's "spheres"—atmosphere,
hydrosphere, geosphere, and
biosphere
• As well as the impact of human
societies on these components.

9. HYDROSPHERE
• All solid, liquid, and gaseous water on
Earth
• Found in the ground, bodies of water, and
in the atmosphere
• Overwhelming majority is salt water (97%)
• (sometimes frozen water put in a separate
sphere called the cryosphere)

10. BIOSPHERE
• All the planet’s living things
• Microorganisms, plants, animals

11. LITHOSPHERE
• All portions of the Earth
• Mantle, core, crust
• (Sometimes its used to describe just the
cold, upper, rocky portion of the Earth

12. ATMOSPHERE
• All air (1m depth to ~10,00km
• Protects Earth from solar radiation
• Retains heat allowing for life
• Weather occurs within it