Chapter 16
Global Climate Change
Mr. Manskopf
Notes also available at
http://www.manskopf.com
Statement: “It has been so hot this
summer, must be that global
warming”
Goals for Chapter 16
► What
is climate?
► What factors determine climate?
► What causes seasonal changes?
► What is the ozone layer and how is it being
altered?
► Describe how human actions are changing
the make up of the Earth’s atmosphere and
what are the potential consequence of that.
Section: Climate and Seasons
GOALS:
► Explain the difference between weather and
climate.
► Identify four factors that determine climate.
► Explain why different parts of the Earth
have different climates.
► Explain what causes seasons.
Audubon’s Climate
Why is Audubon’s climate the way it is?
Weather
► State
of the
atmosphere at any
one time in a region
► What is today’s
weather like?
► What was the weather
like last summer?
► What was the weather
on October 21st
Climate
Climate: is the longterm average
weather conditions
in an area
► Seattle, Washington
► Phoenix, Arizona
► San Diego, Calif.
► Portland, Maine
Climate Factors
1) Latitude: the
distance north or
south from the
equator impacts
a regions climate
► What is 0o, 90o?
► What is
Audubon’s
latitude?
Latitude
Latitude
Greenland at noon in the summer
Dominican Republic Winter
Sun
Climate Factors
2) Atmospheric
Circulation: the
direction the wind
comes from impacts
climate
► Which way
generally does wind
blow across the
U.S.?
Atmospheric Circulation
Prevailing Winds: winds
that blow
predominantly in one
direction
► Westerlies
► Trade Winds
► Polar Easterlies
Climate Factors
3) Ocean Circulation
Patterns: Oceans
carry heat from the
equator or cool
waters from the
poles
► Surface currents
caused by winds
Ocean Currents
Climate Factors
4) Topography:
the shape of
the land
influences
climate greatly
► Mountains can
impact
temperature
and
precipitation
patterns
Topography: Where do you think it
snows the most in the U.S.?
Can it snow near the equator?
Topography
What causes seasonal changes?
When do we get the most direct
sunlight?
Noon
Sunlight
When do we get the most indirect
sunlight?
Noon
sunlight
When is the daylight hours
longest/shortest?
December 21st at 7 PM EST: WHY DOES IT LOOK LIKE THIS
What time of year is this? How do you know?
What 2 days of the year does it look
like this: equal day and not all
around the globe?
Seasons
Seasons:
caused by
the fact that
Earth’s axis
is tilted at
23.5o.
Section Review
► Explain
the difference between weather and
climate.
► Identify four factors that determine climate.
► Explain why different parts of the Earth
have different climates.
► Explain what causes seasons.
Section : Global Warming
GOALS:
► Explain how the greenhouse effect works
► Describe why carbon dioxide is important in the
atmosphere, but why scientists find it troubling
that levels are rising
► Analyze what a warmer world might look like
►DO
NOT CONFUSE OZONE DEPLETION
WITH GLOBAL WARMING!!!
Has Earth’s Climate Always Been
Like Today’s?
► How
is it possible that
you can find shark teeth
20 miles from the beach
in NJ?
► How is it possible that
you find fossils of Palm
Trees in parts of
Canada?
►Today,
global
average temp =
59oF
Has Earth’s Climate Always Been
Like Today’s?
Over past 4.7 billion years
climate has changed by
► Volcanic
eruptions
► Changes in solar output
► Continents moving
► Meteorites
► Natural variations in CO2
Some changes slow, some
quickly
Why does a greenhouse stay
warm in the winter?
Why does the inside of the
car heat up quickly on a
sunny day?
Greenhouse Effect
► Naturally
occurring
process in the
atmosphere where
gases trap in heat.
► Like a blanket
covering planet
► Known about for over
a century
► Without it Earth
would be COLD
Greenhouse Gases
► Major
greenhouse
gases include
► Carbon Dioxide
► Water Vapor
► Methane
► CFCs
► All act to trap in heat
Greenhouse Effect
We know from the past that CO2
levels tied closely to temperature
We know from the past that CO2
levels tied closely to temperature
Measuring CO2
Since 1958 in Mauna Loa Hawaii
What does this
data show?
What trends
does it show?
Why does it go
up and down
each year?
CO2 rates rising
quickly
1764 --- 276 ppm
1995 --- 360 ppm
2010 --- 390 ppm
Chemist Charles Keeling’s CO2
measurements
Why measure here?
Rising CO2 Levels
► Never
390 ppm in last
420,000 years (possibly
20 million)
► Continue to rise rapidly
► Most CO2 in atmosphere
is coming from burning
fossil fuels like coal, oil
and natural gas
► WHAT DOES THAT
MEAN FOR THE
FUTURE?
Where is the CO2 Coming From?
42% Coal powerplants
24% transportation
20% industrial processes
14% residential and
commercial usages
Exhale, drive, turn on light,
burn log in fire
1 gallon of gas burned
equals 20 pounds of CO2
Where is the CO2 Coming From?
4.6% of the world’s
population, yet 24%
of emissions of CO2
From just U.S. coal
burning exceeds 146
other nations with
3/4th of world
population
Per capita yearly 500
tons
What do these graphs tell you?
What do
higher CO2
levels
mean for
our future
climate?
It’s All About Carbon
► http://www.npr.org/templates/story/story.p
hp?storyId=9943298
Global Warming
Earth’s global average
temperature
continues to rise due
to the increase in
greenhouse gases in
the atmosphere
How Can You Predict The Future?
► Very
Complex Computer
Models
► Those models are
saying…
It is likely that the
world will warm 1.4oC
to 5.8oC (2.5oF to
10.4oF) between
2000 and 2100
Why Care? I would like a warmer
winter, and I Love Beach Weather
WHY CARE? It’s not like I can do
anything. Plus, I Love my car.
Some
potential
benefits
of global
warming
Consequences of a Warmer Earth
1) A Grand Experiment
With Potentially Major
Changes
2) Melting Ice = Higher
Seas
3) Change in Weather
Patterns
4) Human Health Problems
5) Agriculture Changes
6) Effects to plants and
animals
Maple Trees in VT
and NH have been
producing less and
less maple syrup
over last few
decades.
Both photos show Sperry Glacier in Montana’s
Glacier National Park. Top: 1913:
Bottom: 2008
Many major
cities in the
world are
below, near or
just above sea
level.
Florida after sea level rise
of 5 meters
Impacts on Organisms
•Habitats shift, usually
toward the poles or to
higher altitudes.
•Migrations start earlier
in
the spring.
•Loss of ice makes
hunting seals difficult
for polar bears
Impacts on the Oceans
•
An increase in ocean
temperature is
associated with a
process called coral
bleaching.
•
Changes in ocean
acidity, resulting from
an increase
in dissolved carbon
dioxide, can harm
organisms.
Reducing Risks
Improve Efficiency of Cars
International Agreements
► What
make Global
Warming a difficult
issue for political
leaders to deal with?
1) Complex Issue
2) Consequences in
Future
3) Need behavior
changes
4) International
5) Wealth Companies
International Agreements
► Why
are international
agreements needed?
► What makes them
hard to negotiate?
► What differences exist
between the
developed and
developing countries?
Kyoto Protocol
► 1997
International
Treaty accepted by
160 countries to
limit CO2 pollution
► 1990 levels by 2012
► U.S. did not ratify
► New treaties trying
to negotiate
Global Warming: What does the
future hold?
Section Review
► Explain
how the greenhouse effect works
► Describe why carbon dioxide is important in
the atmosphere, but why scientists find it
troubling that levels are rising
► Analyze what a warmer world might look like
► DO NOT CONFUSE OZONE DEPLETION
WITH GLOBAL WARMING!!!
(What are some similarities/differences)
Agree or Disagree
► Developed
countries should help countries
with tropical rain forests so those poorer
countries can afford to leave their forests
intact.
► Carbon dioxide is a naturally occurring
molecule and rising levels in our
atmosphere should not be worried about.
Section : The Ozone Shield
GOALS:
► Explain how the ozone layer shields the
Earth from harmful radiation.
► Describe how CFCs are damaging the ozone
layer.
► What are impacts for a thinner ozone layer.
Why is the atmosphere important?
Ozone Layer
Ozone Layer:
► An area of the
stratosphere with
high concentrations
of ozone gas
► Acts like a sun screen
blocking out UV rays
► Ozone = O3
► Good ozone vs. Bad
Ozone
Ozone Depletion
Chlorofluorocarbons
(CFCs)
► Man-made chemical
► “Miracle Chemical”
► Damages the ozone
layer
► Takes a LONG time to
get to ozone layer
and destroys many
ozone molecules
CFCs
► Used
for decades
► Each CFC molecule can
destroy 100,000 ozone
molecules over
decades
Ozone Hole
Antarctic Ozone Levels
Impacts of Thinning Ozone Layer
► Damage
to skin cells
(including skin cancers)
► Damage to eyes
► UV Light damages DNA
► Kills phytoplankton
(single-celled organisms)
which are the base of
most ocean food chains
► UV light damages crops
Wide Ranging Impacts
Protecting the Ozone Layer
Montreal Protocol:
international
agreement in 1987 to
phase out CFC usage
► Second conference in
1992 in Copenhagen
► WHY WILL IT STILL
BE A PROBLEM FOR
MANY MORE
DECADES?
Section Review
► Explain
how the ozone layer shields the Earth
from harmful radiation.
► Describe how CFCs are damaging the ozone
layer.
► What are impacts for a thinner ozone layer.
► DO NOT CONFUSE OZONE DEPLETION WITH
GLOBAL WARMING!!!
(What are some similarities/differences)
► http://www.youtube.com/watch?v=qUfVMogIdr
8