Long Term and
Short Term
Changes in
Climate; The
Albedo Effect
Long Term
Climate
Change
The Cause and Effects
What and How?
 Long
term climate change occurs over
million of years.
 There
are many causes to L.T.C. changes,
such as changes in earth’s orbit, shifting of
continents, and cycle of climate change
Continental Drift
 The
movement of continents.
A
long time ago, there was a single
continent.
 Over
millions of years, the continent “broke
apart” to form present day Earth.
Continental Drift
 Movement
of land affects the climate in
different ways.
 Changes
in ocean currents, wind patterns
and land mass.
 The
result: heat transfer is affected.
Continental Drift.
The Animation.
Cycles
 Not
every type of climate change is
permanent.
 Some
occur in cycles.
 Changes
in Earths orbit also causes
changes in climate and it occurs in
cycles.
Changes in Orbit
 Specific
term: Eccentricity
 The
Earth’s orbit around the sun changes
shape.
 It
changes after around 100 000 years.
 The
reason: Jupiter and Saturn’s
gravitational pull.
Changes in Orbit
 When
the orbit changes, Earths distance
from the sun is either consistent or varied.
 When the distance is consistent, the
seasons are mild.
 When The distance is varied, the climate
tends to be more “extreme”.
Changes in Orbit
 Change
in orbit is a
slow transition from
almost circular to
elliptical.
 The change is very
slow!
 Right now earths
orbit is elliptical.
Tilt
 The
earth slowly
tilts back and forth
on its axis.
 The earth tilts
around 22.1º to
24.5º.
 Happens over
41000 years.
 Currently, earth is
tilted 23.5º.
 This angle is
decreasing.
Tilt
 As
the tilt increases, the so does the
difference in temperature of seasons.
 The Earth also “wobbles” around its axis.
Short Term Factors
Volcanic eruptions
 Changes in the Sun’s radiation
 Changes in air currents
 Changes in ocean currents

Volcanic Eruptions
Rocks, dust and gases are released into
the atmosphere
 The sulfur dioxide particles which are
released reflect the Sun’s energy back
to space
 Since there is less energy, the Earth
cools down temporarily

Volcanic Eruptions

Example on pg. 351 (Fig. 7)
Air and Ocean Currents
Changes in thermohaline circulation can
cause changes in climate
 Thermohaline circulation is the flow of
water around the world’s oceans driven
by differences in temperature and
salinity
 There are some changes which occur
regularly, an example is El Nino

Ocean Currents
(cont.)

Ocean currents affect climate

Example: The air above warm ocean
currents is heated. The land is warmed
and rain is produced when this warm,
moist air reaches land.

This is why air and ocean currents can
affect climate
El Nino
Occurs every 3 to 7 years
 Prevailing winds temporarily change
direction
 Ocean currents change
 Warm water is pushed towards S.
America
 Because of this, the west coast of S.
America gets warm, wet weather

El Nino

On pg. 353
(Fig. 8) in
textbook
The Sun’s Radiation
The amount of radiation the earth
receives affects climate
 Small changes can affect the climate of
the earth
 When the amount of radiation is lower,
there is less energy, the climate cools
 If radiation increases, there is more
energy, the climate warms


Small changes can have large effects

This is because the small changes can be
made bigger because of feedback loops

A positive feedback loop increases the
original cause

A negative feedback loop decreases the
original cause



An example of positive feedback loops is the
water vapour in the atmosphere
More water vapour forms since if the climate
warms. Water vapour is a greenhouse gas and
traps radiation. This further warms up the
earth.
It is the same when the climate cools. Less
water vapour is formed and the climate cools
even more




This is the radiation which is reflected by a
surface
Different surfaces have different albedos, an
example would be ice which reflects much of
the sun’s radiation
The albedo of a planet is a measure of how
much radiation is reflected back when the sun
shines on it
Earth has an albedo of 0.30-0.40





This is an important feedback loop in Earth’s
climate
It is a positive feedback loop
Relationship between ice on surface of the
Earth and the avg. temperature
If the temperature increases, ice melts and
less radiation is reflected which further
increases the temperature
If it decreases, ice forms and more radiation is
reflected
1.
2.
3.
4.
5.
6.
What are the long term changes affecting
the earth?
What is continental drift?
What can the movement of large land
masses cause?
Does the orbit of the earth change? How?
What are the short term changes which can
affect climate?
How do volcanic eruptions cause changes in
climate?
What is albedo?
8. What is the albedo effect?
9. What happens if the temperature of the
planet increases?
10. What happens if the teperature of the planet
decreases?
7.