GEOGRAPHY 1000
Introduction to Physical Geography
Lithosphere
Hydrosphere
Atmosphere
Biosphere
Understanding the Earth’s
natural environment from
local to global scales
Your course instructor
Dr. Matthew G. Letts
matthew.letts@uleth.ca
WE2052, 403-317-2842
Ph.D.
M.Sc.
B.Sc.
B.A.
Geography
Geography
Geography
Biology
University of London (King’s)
McGill University
Queen’s University
Queen’s University
2003
1998
1995
1994
Interests: Plant ecology, microclimatology, hydrology and soils
Where? Canada, Colombia and France
Where are
you from ?
Where are you from?
What is the landscape like?
What kind of weather do you get?
What kind of plants grow there?
How do people use natural resources?
WHY?
Are there environmental problems?
What are the solutions?
The Earth’s
Four Spheres
Lithosphere
Hydrosphere
Atmosphere
Biosphere
Who discovered
the spherical
Earth?
Not Cristóbal, Colón !
Eratosthenes even knew the
circumference in 247 BC.
Knowledge of a spherical Earth
Ancient Greece
Pythagoras (2506 - 2581 BP)
Aristotle proved Earth to be spherical in (2395 - 2333 BP)
Ancient Egypt
Eratosthenes calculated the polar circumference (2258 BP)
Incan astronomers
Accurately calculated the precession of the equinoxes
England:
Newton predicted that Earth bulges slightly at equator (324 BP)
Today: Geodesy - Earth’s shape and size characterized by
surveys and mathematical calculations – Geoid
How do we display the
Earth in two dimensions?
How did you do?
Latitude
Longitude
GEOGRAPHY
Geo (“Earth”) + Graphein (“to write”)
Geography is the study of synergistic interactions
among natural systems, geographic areas,
society, and cultural activities over space
Spatial analysis is the key to geography
•The nature and character of physical space
•Human-environment interactions and the spatial
& temporal distribution of human behaviour
and Earth system processes
What is Physical Geography ?
“The spatial analysis of all the physical elements
and processes that make up the environment:
energy, air, water, weather, climate, landforms,
soils, animals, vegetation and Earth itself.”
Physical Geography is an Earth Systems
Science. As a science, it employs the scientific
method
The main concept of Earth Systems science is
That “interacting physical, chemical and biological
systems produce the conditions of the whole
Earth.”
Understand
Environmental
Problems
The scientific method
A small
scale
system
Global Carbon Balance: large system
Open Systems
•
•
•
•
Permeable to energy and mass*
Energy can be supplied by the surrounding environment
Inputs and outputs can cross back and forth between
the system and the surrounding environment
The Earth is an open system in terms of energy but is
nearly closed in terms of matter
Closed Systems
•
•
•
•
Self-contained from the surrounding environment
Not permeable to energy and mass*
Truly closed systems do not exist, using the natural
science definition
Theoretical construct: energy can never increase,
entropy can never decrease
N.B.: Physicists may refer to a closed system as one in which
there is exchange of energy but not matter
Positive feedback
•Further production in the system leads to growth in the system
Example:
1.Greenhouse gas emissions cause warming
2. Warming causes melting of polar ice
3. Reduced reflectivity causes more warming
4. Warming causes more release of greenhouse gases
from oceans and landmasses
•Aspects of systems may reach critical thresholds causing
instability
Negative feedback
The higher the temperature of a body, the more infrared
radiation is emitted
Over certain time scales, Earth temperatures have been in a
state of dynamic equilibrium, but there is concern that there may
be thresholds or tipping points that could destabilize the system.
Global monthly average surface air temperature since 1979
(Source: Hadley CRUT).
What is your passion?
Outdoor adventure?
Undergraduate
Field Trips
Apply what you
learn in class
and in the lab
Summer Research
GIS: Solve problems from indoors too!