Transcript Ozone Depletion and Global warming ppt angie

Global Environmental Change
Climate Change, Global
Warming, Ozone
Depletion…
…what’s going on?
Stratospheric Ozone Depletion
What are Halogen Gases?
Where do CFC’s come from?
Where else can we find Ozone
depleting chemicals?
What are the key sources of Ozone
depleting chemicals?
How has Ozone Changed over
Antarctica?
What does Ozone thinning look
like in the Artic.
How long do CFC’s last???

The chlorine atoms can break down tens of
thousands of ozone molecules before being
removed from the stratosphere. Given the
longevity of CFC molecules, recovery times are
measured in decades. It is calculated that a CFC
molecule takes an average of 15 years to go
from the ground level up to the upper
atmosphere, and it can stay there for about a
century, destroying up to one hundred thousand
ozone molecules during that time.
Montreal Protocol
After a series of rigorous meetings and negotiations, the
Montreal Protocol on Substances that Deplete the Ozone
Layer was finally agreed upon on 16 September 1987 at
the Headquarters of the International Civil Aviation
Organization in Montreal. The Montreal Protocol stipulates
that the production and consumption of compounds that
deplete ozone in the stratosphere--chlorofluorocarbons
(CFCs), halons, carbon tetrachloride, and methyl
chloroform--are to be phased out by 2000 (2005 for methyl
chloroform). Scientific theory and evidence suggest that,
once emitted to the atmosphere, these compounds could
significantly deplete the stratospheric ozone layer that
shields the planet from damaging UV-B radiation.
Back to the Troposphere
What is Climate?

Climate = the average and variations of
weather over a long period of time (~30
years)
Above: Global average for atmospheric water vapor.
What is Weather?

Weather = all natural phenonmena
within the atmosphere at a given
time (hours to days)
Modern Climate Systems

Atmospheric circulation
Modern Climate Systems

Atmospheric circulation
Sunlight
The Climate System
Oceans
Atmosphere

Ice
Biosphere
Land
The Earth has
many different
systems that
interact with each
other in different
ways.
Modern Climate Systems

Ocean circulation
Sinking cool water,
rising warm water
and wind help to
form global ocean
current systems.
The Great Ocean Conveyor
Modern Climate Systems

Atmosphere and Greenhouse Effect


The Earth’s atmosphere keeps it around
30°C warmer than it would otherwise be.
This is the Greenhouse Effect
What is the Greenhouse Effect?
The temperature of the Earth
depends on the amount of
energy we receive from the
sun versus the amount of
energy lost back out to space.
cc. Robert A. Rohde (Global Warming Art)
Past Climate Systems

How do we know about climate systems in
the past?
Past Climate Systems
1. Early human record
cc. W.V. Bailey
Rock paintings provide evidence of
fertile Sahara region (now desert)
6,000 years ago.
Tourism NT http://www.travelnt.com
Past Climate Systems
2. Geomorphology
River deltas
show where
rivers entered
the ocean or a
lake.
Above: A “U” shaped valley
shows that it was formed by
a glacier.
Past Climate Systems
3. Geological record
Fossils preserve evidence of past life.
Drilling into the ground can recover rock
layers that record what conditions were
like when the rock was deposited.
Past Climate Systems
4. Ice cores
Ice cores can preserve
seasonal layering.
Studying the chemistry of
each layer can give clues
about climate change.
GISP2 ice core at 1837m depth with clearly visible annual layers.
Is the Climate Changing?
What are the current climate trends?
Global temperature for the
last 150 years
cc. Robert A. Rohde http://www.globalwarmingart.com/wiki/Image:Instrumental_Temperature_Record_png
What are the current climate trends?
cc. Robert A. Rohde http://www.globalwarmingart.com/wiki/Image:Global_Warming_Map_jpg
Looking further into the past…
Global temperature for the
last 1000 years
cc. Robert A. Rohde http://www.globalwarmingart.com/wiki/Image:1000_Year_Temperature_Comparison_png
What causes it?
Human ImpactsGreenhouse Gases:
*CO2
*methane
*nitrous
oxide
*fluorinated
compounds
Anthropogenic Influence





Fossil fuel
Aerosols
Cement
manufacture
Land use
Livestock
cc. Robert A. Rohde
http://www.globalwarmingart.com/wiki/Image:Carbon_Dioxide_400kyr.png
Who’s Responsible?

Burning of fossil
fuels is main cause
•U.S. is leader in
greenhouse gasses
•Human impacts are
changing the
composition of the
atmosphere
What causes it?

Natural Impacts:
*Change in sun’s
energy output
*Volcanoes
*clouds
*Water vapor
The Carbon Cycle
Future predictions…


Based on no
changes in
emissions
(“business as
usual”)
The U.S.
would be 23.5°C hotter
on average.
cc. Robert A. Rohde http://www.globalwarmingart.com/wiki/Image:Global_Warming_Predictions_Map_jpg
What does it all mean?




Sea level rise
More extreme
weather
Changes in
precipitation
Spread of disease
cc. Robert A. Rohde
http://www.globalwarmingart.com/wiki/Image:Recent_Sea_Level_Rise_png
What’s all this talk about
Arctic Ice increasing?

http://nsidc.org/news/press/20091005_mi
nimumpr.html
Questions to be answered…






How fast will the sea level rise?
How much warmer will it get?
When will the Arctic Ocean be ice-free?
Will the water cycle accelerate?
Are climate extremes increasing?
Will there be abrupt changes?
Boiling Frog Syndrome
Science can provide
knowledge…
…We all have to
provide the solutions.