Notes: present change and future climate

Please get out homework for
a stamp: Two questions on
RCP’s, bracket map, 10 terms
Please read the board.
Kahoot practice! 
What do these have in
Climate and civilization
Human civilizations change when climate
 20,000 ybp (years before present) ice age:
Bering strait freezes, people migrate to the
 8,000-7,000 ybp – warming period
Mesopotamia flourishing, Jericho
suddenly 950 CE (common era – used to
be called AD)
Leif Erikson – 950 CE sails to
from China
Little Ice age – 1550-1850
Irish Potato Famine
Dust Bowl – 1930’s
Mild but persistent La
Nina conditions
coupled with changes
of sea surface
temperatures + poor
farming practices
SPM 1: Current observations
What details need to
be added?
Correlation/causation pg 5
CO levels currently
Mauna Loa Observatory - Hawaii
CO2 at beginning of Industrial revolution: 280 ppm
Current CO2 levels: 398ppm
(watch the movie – when is CO2 highest? Where???
Figure 4 – Current observable
Circle most certain effects
 What are the implications?
 Examples from the news?
 Which is of greatest concern to
SPM figure 5
What are the predictions?
 How do they get from CO2 to change in
Predicting future
How do they do that anyway?
Global Circulation model
Global Climate Models: GCM’s
Computer model divides atmosphere into
 Current conditions programmed into each
chunk: temp, wind, [GHGs], etc
 Computer can generate current and future
global temperature averages based on
Limitations of GCMs
Feedback loops (not included in GCMs)
(+)Melting tundra permafrost and lower geologic formations– 500
billion tons CH4
(+)Loss of albedo effect with ice
(-)Increasing albedo effect with clouds
(+) Increasing greenhouse effect with evaporating water
Role of ocean and CO2 absorption
Lesson from the Ozone Hole:
1930’s – CFCs invented
 1970’s – mechanism of O3 destruction
understood; models of possible effects
suggest general thinning of O3 layer
 1985 – Ozone hole documented as
complete surprise – models were wrong.
 1987 – Montreal Protocol ratified
If CO2 goes to 450ppm by 2050, +2oC (3.6oF)
CO2 to 550ppm by 2050, +3oC (5.4oF)
In 50 yrs, expect 4oC warming (2012 World Bank Report)
CO2 of 350ppm is considered sustainable by
Tipping point is probably at 2oC
(the point at which change due to human activity
brings about sufficient new processes in nature to
make any human reversal of the change impossible. )
Homework tonight
Read SPM 2.1 and 2.2 add details to your
bracket map.
 to review terms: search
IPCC terms WHS or carolynklein
Chasing Ice –
ice core graphs, effects, glaciers
Big seven effects
Change in precipitation patterns
More severe weather events (droughts, floods,
extreme hot/cold)
Rising sea levels (glaciers melting)
Changing seasons – earlier spring and shift of
biomes away from equator
Increased insect-borne disease
Decreased availability of fresh water
Acidification of ocean and bleaching of coral reefs
Sea level rise .7 m by 2100
Melting glaciers add water volume to
ocean (Greenland ice sheet stores enough water to
raise sea level by 5-7 meters)
Thermal expansion creates most of the
Where will the environmental refuges
go? 50% of global population lives
within 100 miles of a coastline.
Shift of biomes away from equator
can shift
through seed
of habitat
to higher
latitudes and
loss of
Fig. 11–9
© Brooks/Cole Publishing Company / ITP
Don’t forget!