Heat Budget and Climate
Change
Heat Budget is the result of a balance between energy received (insolation and Earth’s Interior)
and energy lost (terrestrial radiation) for an object. An object’s heat budget can be measured as
an average temperature.
Long term changes in the Earth’s Heat Budget can lead to climate change.
CLIMATE CHANGE
During Earth’s History, Earth’s heat
budget has shifted between cooling and
warming trends. Cooling trends have led
to the advancement of glaciers in the
middle latitudes. These cooling trends are
referred to as
ice ages.
Ice Ages and
Warm Trends
CLIMATE CHANGE
El Nino / La Nina.
Periodically the
temperatures of
ocean waters shift
from cooler to
warmer
temperatures and
vice versa. These
temperature
changes can lead
to shifts in the
heat budget.
El Nino
CLIMATE CHANGE
Warm water influx off of the
coast of South America
In a La Nina event, exceptionally
colder waters replace the cool water
off of the coast of South America.
This, in turn, leads to climatic change
affecting the heat budget.
Every 2- 10 years
the prevailing
wind patterns shift
in the Pacific
Ocean pushing
warmer water off
of the west coast
of South America
– known for its
cooler water. This
influx of warm
water can lead to
a rise in
temperature, air
convection and
precipitation for
various locations
around the Earth.
The heat budget of
the planet will
change.
CLIMATE CHANGE
Global
Warming
In modern history, there
has been a trend of rising
average temperatures
around the Earth. Much of
Earth’s long-wave
radiation is staying
trapped in our atmosphere
instead of escaping into
space. Violent storms and
heat waves are becoming
more common due to
global warming. As a
result the heat budget for
the planet is changing.
CAUSES FOR CHANGE IN HEAT BUDGET
A sunspot represents a
darker region of the Sun’s
surface. The presence and
absence of sunspots in
cyclical. When sunspots
appear in large numbers,
there is an increase in
electromagnetic energy
that reaches the Earth.
This can cause an increase
in the heat budget.
Change in Solar Energy
CAUSES FOR CHANGE IN HEAT BUDGET
Over periods of thousands of
years the Earth’s tilt and its
eccentricity in its orbit
around the Sun changes
slightly. This can alter the
intensity and amount of
insolation the Earth receives
– thus, altering the heat
budget for the planet.
When our orbit’s eccentricity
AND tilt are altered at the
same time; the climatic
change is profound (Ex:
increase in glaciation and the
emergence of an Ice age) .
Change in Earth’s Orbit and
Tilt
CAUSES FOR CHANGE
IN HEAT BUDGET
Volcanic
Eruptions
Some volcanic
eruptions are quite
intense and release a
large amount of
aerosols (volcanic
ash, sulfur
compounds, etc…) into
the atmosphere.
These aerosols
remain in the
atmosphere for some
time – reflecting
insolation from the
Sun. Thus the heat
budget for the planet
will be altered. The
Earth will be cooler.
CAUSES FOR CHANGE
IN HEAT BUDGET
Human Causes
The activities of humans have
led to changes in the planet’s
heat budget.
Deforestation = less insolation
absorbed by plants; less precipitation.
Urbanization =clearing of land for
constructing of cities; increase in
CO2 in atmosphere.
Desertification = overgrazing of land leads to
the spread of deserts; temperature increase.