milankovich Lesson

Long-Term Climate

Change

Nov. 13-Milankovitch Cycles

During an El Niño year, there is
increased precipitation in the Southern
United States, but the north is warmer
and dry. Where does the moisture
causing the precipitation in the South
come from?

🐢 the Pacific Ocean

🐇 the Gulf of Mexico

😀 the polar jet stream

🔊 the southern Atlantic Ocean

🐇 the Gulf of Mexico

the El Niño winter rainfall

anomalies for the continental

United States. Many portions of the

U.S. typically have near normal
rainfall under El Niño conditions.
However, the Ohio Valley is below

normal, and the southern tier of

States from California to Florida is

above normal with some spots
averaging as much as 5 inches
above normal. Storms making
landfall in California and storms
developing in the Gulf of Mexico

are the culprits.

Multiple Choice

During an El Niño year, there is
increased precipitation in the Southern
United States, but the north is warmer
and dry. Where does the moisture
causing the precipitation in the South
come from?

• 🐢 the Pacific Ocean

• 🐇 the Gulf of Mexico

• 🔊 the southern Atlantic Ocean

• 😀 the polar jet stream

Class Norms

Audio Response

Make a silly noise and feel a little better

Open Audio Recorder

Standard

SEV2. Obtain, evaluate, and communicate
information to construct explanations of
stability and change in Earth’s ecosystems.

a. Analyze and interpret data related to
short-term and long-term natural cyclic
fluctuations associated with climate change.

(Clarification statement: Short-term
examples include but are not limited to El
Niño and volcanism. Long-term examples
include but are not limited to variations in
Earth’s orbit such as Milankovitch cycles.)

Learning Target

I can describe how changes in
Earth’s orbit affect the amount of
solar radiation that enters Earth’s

atmosphere.

What was affected by the amount of solar
radiation in a certain spot on the planet?

Basketball

●Do you know what it is?

●Ever here about the Harlem
globetrotters?

Are the balls rotating or revolving?

Long-Term Environmental Change

Long-term environmental
change takes place over
thousands to hundreds of
thousands of years.

Remember that the Earth is 4.5
billion years old and 100-200 years
are short-term when compared to
the age of the Earth.

Evolution and Adaptation

Long-term environmental
changes to our climate
happen so slowly that
populations are able to
evolve and adapt to the
changing climate.

When the climate changes
too fast, populations do
not have enough time to
evolve and many go
extinct.

Milankovitch Cycles

Milutin Milankovitch
hypothesized that
changes in Earth’s
position as it orbits the
sun affects the amount
of solar radiation that
enters our atmosphere
causing changes in
Earth’s climate.

He formed a
mathematical model
that explained Earth’s
varying orbit around
the sun.

When the Earth’s orbit around the sun is more
circular, will we have more extreme seasons or more
mild seasons?

🐢 Really hot summer and really cold winters.

🐇 Warm summers and cold winters.

Multiple Choice

When the Earth’s orbit around the sun is more
circular, will we have more extreme seasons or more
mild seasons?

• 🐢 Really hot summer and really cold winters.

• 🐇 Warm summers and cold winters.

• Really hot winters and cold summers

• Ice age with megafauna

When the Earth’s orbit around the sun is more
circular, will we have more extreme seasons or more
mild seasons?

🐇 Warm summers and cold winters.

When the Earth’s orbit is more
circular, there are smaller
fluctuations in the distance
between the Earth and the
sun meaning the seasons are
milder.

When e=0 then the northern
and southern hemispheres
experience about the same
amount of solar radiation
during their respective
summers.
e=eccentricity

Seasons
What season is it now?

Why do we have seasons?

Seasons

We have seasons because of the Earth’s tilt. The side of the
Earth that is tilted towards the sun experiences summer
because it is getting more solar radiation.

As the Earth orbits the
sun, the side of the
Earth that is tilted
towards the sun
changes and we
experience a changing
of seasons.

What would the
seasons be like if
the Earth was not
tilted on its axis?

In the group feature in Canvas look at the questions and use the websites to find answers to the questions for example...

​

BrainPOP ice age

Question:
- Estimate the time period of one complete cycle of precession.
-

​Answer

Precession – As Earth rotates, it wobbles slightly upon its rotational axis, like a slightly off-center spinning toy top. This wobble is due to tidal forces caused by the gravitational influences of the Sun and Moon that cause Earth to bulge at the equator, affecting its rotation. The trend in the direction of this wobble relative to the fixed positions of stars is known as axial precession. The cycle of axial precession spans about 25,771.5 years

Nearpod Challenge Milankovitch style

●3 challenges and a video

https://app.n
earpod.com/
?pin=KGTF5

What kind of environmental changes do the
Milankovitch cycles represent.

🐢 Ecological Succession

🐇 Short-term Changes

😀 Secondary Succession

🔊 Long-term Changes

Multiple Choice

What kind of environmental changes do the
Milankovitch cycles represent.

• long-term climate change

• short-term climate change

• secondary succession

• ecological succession

What kind of environmental changes do the
Milankovitch cycles represent.

🐢 Ecological Succession

🐇 Short-term Changes

😀 Secondary Succession

🔊 Long-term Changes

The shortest of
these cycles
(Precession) lasts
23,000 years.

How did you do?

Learning target in question form
If you scored less than an 80 on
some part of the assignment, try it
again until you can answer the
questions with higher than an 80.

Remember: This is a graded
assignment with unlimited attempts.
You can redo parts of it to improve
your grade.

Lesson Summary

➢Earth’s climate is and has always been
changing.

➢The Milankovitch cycles describe the change in
Earth’s orbit around the sun and slowly affect
climate over tens of thousands to hundreds of
thousands of years.

➢Eccentricity measures how elliptical Earth’s
orbit around the sun is.

➢Obliquity is the measurement of Earth’s axial
tilt.

➢Precession is the change in where the Earth’s
axis is pointed. Today the Earth’s axis is
pointed at Polaris, but it is slowly pointing away
and in 11,500 years it will be pointing at Vega.

➢The Milankovitch cycles affect how much solar
radiation enters our atmosphere. More solar
radiation = a warmer climate.

➢The more extreme the changes, the greater
variations of temperature as the seasons
change.

Polar Ice Caps Melting

Since the industrial revolution,
humans have been digging fossil fuels
out of the ground and burning them
as fuel to better our lives.
Unfortunately we have largely ignored
the effects the CO2 emitted by
burning fossil fuels has been having
on our climate.
Today the increased temperatures is
causing the polar ice caps to melt
which decreases the salinity of our
oceans and raises sea levels. Sea ice is
taking longer to form in the winters
and faster to melt in the summers
and wildlife, like polar bears, are
losing their habitats and starting to go
extinct.

Keeping Track on Human Impact