# Notes: Historical Climate

```Are you ready for the quiz?
Review yesterday’s notes in interactive
notebook.
 Practice with objectives #1-4.

Climate – on a geologic
scale – WAAAAY back in the day!
First, try this:
Take the average of the following
numbers: 100, 0
 Take the average of
100,100,100,100,100,100,100,100,100,&amp;
0
 (that’s 9 sets of 100)

How does having
more data affect an
average?
Your GPA is a lot harder to
change than a progress report
complete the
worksheet
Interactive notebook: New page
Title: Historical Climate
 Date: April 14

Cut out Graph A and glue it onto the right
side. Leave space below for notes
 Title the graph Historical Climate Change

*Graph: Three important inferences
Climate change is natural on Earth
 100,000 year cycles between glacial
maximum (ice age) and interglacial
periods (maximum warmth)
 A change in -3oC can create an ice age

A change of 1o is significant
Global average temperature = 59oF
 Current CO2 concentration = 398ppm
 (changing your GPA is much harder than
changing a progress report average in one
class)

Observations?
*Milankovitch cycles

Combination of these effects creates
100,000 year cycle of warming and cooling
Earth’s orbit
around the sun
Ice core sampling
We are changing the carbon cycle – burning
ancient carbon (fossil fuels) moves C into
the air.
*Climate and civilization
Human civilizations change when climate
changes
 Farming relies on predictable weather

Mayan civilization – collapses suddenly 950
CE (common era – used to be called AD)
Leif Erikson – 950 CE sails to Greenland
Black Death in Europe – famine 1315-1317 – needed to
import grain from China
Little Ice age – 1550-1850
Irish Potato Famine
Dust Bowl – 1930’s

drought+ poor
farming practices
Wrap it up!
Which is surprising to climatologists – that
the climate changes or the current rate of
change?
Has climate always been the same on
Earth?
What are Milankovitch cycles?
How do we depend on predictable climate?
```