Climate of the Future
• What is the “consensus” on how climate will
change?
Or
How characterize the predictions that are
currently predominant in the popular media?
• What are the big, scariest impacts you’ve
heard about?
• What are the fundamental assumptions that
underlie or bolster these predictions?
Geography
• What is it?
• What sets it apart from other disciplines?
Geography
Earth System Science
• Recognition that earth is made up of a bunch
of interconnected, interdependent systems.
• What is a system?
•
“A collection of interacting objects.”
• A system consists of three basic elements:
– a functioning set of components,
– a flow of energy which powers them, and
– a process for the internal regulation of their
functioning called feedback
Earth System Science
• Recognition that earth is made up of a bunch
of interconnected, interdependent systems.
• What is a system?
• What are the primary components of the
Earth System?
Earth System Science
Open vs. Closed Systems
• What is the difference between an open and
closed system?
• Is the Earth an open or closed system?
• Example of an open system?
• What about a fish tank?
• Example of a closed system?
Cycling
• Continuous cycling of energy and mass
between the different spheres.
• Nutrient Cycling
– Carbon, Nitrogen
• Hydrologic Cycling
Cycling
• Continuous cycling of energy and mass
between the different spheres.
• Biogeochemical Cycling
– Carbon, Nitrogen
• Hydrologic Cycling
Cycling
• Continuous cycling of energy and mass
between the different spheres.
• Biogeochemical Cycling
– Carbon, Nitrogen
• Hydrologic Cycling
• Example of energy being transferred from one
sphere to another?
Cycling
• Continuous cycling of energy and mass
between the different spheres.
• Biogeochemical Cycling
– Carbon, Nitrogen
• Hydrologic Cycling
• Example of energy being transferred from one
sphere to another?
System Regulation
• Most systems tend toward a state of
equilibrium where system inputs are balanced
by system outputs.
• The state of natural systems oscillates around
a mean condition – a state known as dynamic
equilibrium.
• Examples?
Dynamic Equilibrium
System Regulation
• System regulated, dynamic equilibrium
achieved – via feedbacks.
• Positive Feedbacks vs. Negative Feedbacks
• Examples?
Negative Feedback
Gaia Hypothesis
• The idea that the Earth reacts like an
organism.
• For example, the theory that the relatively
stable conditions on Earth (atmospheric gas
composition, temperature, etc) is due to the
regulatory influence of the biosphere over the
atmosphere.
• If some perturbation causes environmental
conditions to shift, activities of the biosphere
bring them back into balance.
Gaia Hypothesis
• The output of the sun has increased since the time our
galaxy was formed. As a result, more solar radiation
has been reaching the earth through time.
• However, over long periods of geologic time the air
temperature has not changed all that much.
• Scientists argue that this has been accomplished
through various biospheric regulatory mechanisms that
alter the gaseous composition of the atmosphere and
the nature of the earth surface.
• According to James Lovelock, the Earth is now slipping
into a fever. Biospheric regulatory mechanisms can no
longer cope.
Positive Feedback
What Kind of Feedback?
What Kind of Feedback?
What Kind of Feedback?
Tipping Points
• Some stress continues long enough (chronic)
or is strong enough over a short period (acute)
to take system to a new equilibrium state.
• James Hansen (NASA) - A tipping level (point)
is a level at which "no additional forcing is
required for large climate change and
impacts."
% Coral
Coming to a New Equilibrium
New Equilibriums
From Raskin et al, 2004
New Equilibriums
From Raskin et al, 2004
In Preparation for Mapping Lab and an
Example of an Earth System
• The Magnetic Field
• An interaction between the lithosphere and
atmosphere (and outer space)
The magnetosphere
shields the surface of
the Earth from the
charged particles of
the solar wind and is
generated by electric
currents located within
the Earth’s crust.
The Magnetic Field
• The origin of the Earth's magnetic field is not
completely understood, but is thought to be
associated with electrical currents produced by the
coupling of convective effects and rotation in the
spinning liquid metallic outer core of iron and nickel.
This mechanism is termed the dynamo effect.
• The rotation of the Earth plays a part in generating the
currents which are presumed to be the source of the
magnetic field. Venus does not have such a magnetic
field although its core iron content must be similar to
that of the Earth. Venus's rotation period of 243 Earth
days is just too slow to produce the dynamo effect.
•
•
http://csep10.phys.utk.edu/astr161/lect/earth/magnetic.html
http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/magearth.html
Magnetic Field
Earth's Core, Magnetic Field Changing Fast, Study Says
Kimberly Johnson for National Geographic News
June 30, 2008
Hold on Tight! Earth's Magnetic Field May Be Preparing
to Flip!
The magnetic field has been getting weaker, decreasing
by about 5% each century. This might be a sign that a
magnetic field reversal is beginning. That's when the
North and South magnetic poles flip! Magnetic
reversals happen on average every 250,000 years, but
it has been 750,000 years since the last reversal.
http://www.windows.ucar.edu/tour/link=/headline_universe/earth_science/stories_2003/mag_reverse.html
Magnetic Field
Declination of Magnetic Field
Interaction of a Compass with the
Earth’s Magnetic Field
• http://www.windows.ucar.edu/tour/link=/phy
sical_science/magnetism/earth_magnet_dipol
e_interactive.html&edu=high
Declination
Declination Over Time