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."

Coming to a New Equilibrium%

Cor

al

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 SaysKimberly Johnson for National Geographic NewsJune 30, 2008

Hold on Tight! Earth's Magnetic Field May Be Preparing to Flip! http://www.windows.ucar.edu/tour/link=/headline_universe/earth_science/stories_2003/mag_reverse.html

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.

Magnetic Field

Declination of Magnetic Field

Interaction of a Compass with the Earth’s Magnetic Field

• http://www.windows.ucar.edu/tour/link=/physical_science/magnetism/earth_magnet_dipole_interactive.html&edu=high

Declination

Declination Over Time