Transcript Global Warming

GLOBAL CLIMATE CHANGE
INTRODUCTION
• "The Earth's well-being is also an issue
important to America. And it's an issue
that should be important to every nation
in every part of our world. The issue of
climate change respects no border. Its
effects cannot be reined in by an army nor
advanced by any ideology. Climate
change, with its potential to impact every
corner of the world, is an issue that must
be addressed by the world."
-- President Bush, June 11, 2001
WHAT IS CLIMATE CHANGE?
• climate change is the departure from the
expected average weather or climate
normals (temperature and precipitation)
for a given place and time of year.
• Is our climate changing?
• How do you know? Is there proof? Is it
valid?
COMPOSITION OF THE EARTH’S
ATMOSPHERE
CONSTANT COMPONENTS – Proportions remain the
same over time and location
Nitrogen (N2) 78.08%
Oxygen (O2) 20.95%
Argon (Ar) 0.93%
Neon, Helium, Krypton
0.0001%
VARIABLE COMPONENTS – Change over time
Carbon dioxide (CO2)
0.0003%
Water vapor (H20) 0-4%
Methane (CH4)
trace
Sulfur dioxide (SO2) trace
Ozone (O3) trace
Nitrogen oxides (NO, NO2) trace
EFFECTS OF THESE GASSES ON
OUR EARTH.
• Nitrogen and oxygen are essential to human life
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on the planet - they have little effect on weather
and other atmospheric processes.
The variable components, which make up far
less than 1% of the atmosphere, have a much
greater influence on both short term weather
and long term climate.
For example, variations in water vapor in the
atmosphere are familiar to us as relative
humidity.
GREENHOUSE GASSES
• Water vapor, carbon dioxide, methane,
nitrous oxide, ozone, CFC’s all have an
important property: they absorb heat
emitted by the earth and thus warm the
atmosphere, creating what we call the
“greenhouse effect.”
• Without these so-called greenhouse gases,
the surface of the earth would be about
30 degrees Celsius cooler - too cold for life
to exist as we know it.
GREENHOUSE EFFECT
• Though the greenhouse effect is sometimes
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portrayed as a bad thing, trace amounts of
gases like CO2 warm our planet’s atmosphere
enough to sustain life.
Diagram on Board
GLOBAL WARMING
• Global warming, on the other hand, is a
separate process which can be caused by
increased amounts of greenhouse gases in
the atmosphere.
OTHER INFLUENCES ON THE
ENVIRONMENT
• Besides gases, the atmosphere also contains
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particulate matter like dust, volcanic ash, rain,
and snow.
highly variable and are generally less persistent
than gas concentrations
they can sometimes remain in the atmosphere
for relatively long periods of time.
Volcanic ash from the 1991 eruption of Mt.
Pinatubo in the Philippines, for example,
darkened skies around the globe for over a year.
EARTH’S PAST ATMOSPHERE
• Though the major components of the
atmosphere vary little today, they have
changed dramatically over the entire age
of the earth, about 4.6 billion years.
• The early atmosphere was hardly the lifesustaining blanket of air that it is today;
– most geologists believe that the main
constituents then were nitrogen gas and
carbon dioxide, but no free oxygen.
THE KYOTO PROTOCOL…
• What is this all about…
What else do you need to know???