Transcript L17-GlobalWarming08

Revised Papers due April 17

Strunk and White, The Elements of Style.
Note: The guidelines indicated in the “Revisions
Instructions” (posted on the web) must be
followed precisely for the revised paper to be
accepted.
Global Warming
NEWS: later
NEWS:
Wilkens Ice Shelf is disintegrating
Last Class…
What is the definition of a greenhouse gas?
What are examples of greenhouse gases?
What is the most effective greenhouse gas?
NEWS: later
Absorbers in our Atmosphere
Earth emits much of its radiation here.
CO2 and H2O are the most important greenhouse gases.
Last Class…
Power*: P = T4
For Earth:
Power* In
Power* out
235 W/m2
235 W/m2
Power* In
Power* out
229 W/m2
229 W/m2
T = 253 K or -3o F
For Venus:
T = 252 K or -3o F
We argued that the energy/sec of sunlight into the atmosphere
equals the energy/sec out of the atmosphere. NEWS: later
 = 5.67x10-8 W/m2 K4
Last Class…
Power*: P = T4
For Earth:
Power* In
Power* out
235 W/m2
235 W/m2
Power* In
Power* out
229 W/m2
229 W/m2
T = 253 K or -3o F
For Venus:
T = 252 K or -3o F
We argued that the energy/sec of sunlight (and IR radiation) into
the atmosphere equals the energy/sec out of the
atmosphere.
NEWS:
later
 = 5.67x10-8 W/m2 K4
Power
balanc
e
Infrared
Radiation
Visible
Sunlight
Correction: The power of sunlight and
IR light entering the atmosphere equals
the power of IR light exiting the
atmosphere
Infrared
Radiation
Visible
Sunlight
Our assumption: The power of sunlight
entering the atmosphere equals the
power of IR light exiting the atmosphere
VENUS vs EARTH
Venus
Earth
92 bar
1 bar
Surface Temperature
735 K (872 F)*
288 K (59 F)
Bulk Density (g/cm3)
5.245
5.512
Radius (km)
6052
6378
N2
3.5%
78%
CO2
96.5%
0.038%
Surface Pressure
* Hot enough to melt lead
VENUS vs EARTH
Venus
Earth
92 bar
1 bar
Surface Temperature
735 K (872 F)*
288 K (59 F)
Bulk Density (g/cm3)
5.245
5.512
Radius (km)
6052
6378
N2
3.5%
78%
CO2
96.5%
0.038%
H 2O
0%
3%*
Surface Pressure
* But there is 1000 times this amount on the surface!
Runaway Greenhouse: Recipe*
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Heat Earth with CO2 , H20 evaporates.
Water further heats Earth.
More water then evaporates.
This causes more heating.
More water evaporates.
And so on.
* Easier than instant pudding
Topic: Global Warming
Science & Society
Today’s Lecture includes:
Why no life on Venus?
Are we affecting Earth?
Saucy political intrigue.
NEWS: later
QuickTime™ and a
decompressor
are needed to see this picture.
The Increase in CO2
Measuring Earth’s
temperature
1) Thousands of thermometers on weather stations &
2)
3)
4)
5)
6)
7)
8)
ships
Satellite microwave emission from O2 (lower 5
km)
Measure change of temperature with height.
Greenhouse warming causes the lower 5-10 km to
heat and above to cool.
Make measurements throughout the day, everyday.
Isotopic composition in ice cores (Past climate)
Coral growth (Past climate)
Tree ring widths. (Past climate)
Human records, e.g. the freezing of the Thames
(London).
USGS core lab
Date by counting layers, Volcanic eruptions…
Colder temperatures: lighter H & O isotopes
(for which H2O has a higher vapor pressure).
Evidence that Earth is warming
Reconstruction of the Northern Hemisphere temperatures coral and ice-core proxy records
(Mann et al. 1999, 1998, Jones & Briff 1992)
Figure 3.1
IPCC
Intergovernmental
Panel on Climate
Change
February 9, 2007, Paris
Figure 3.10
IPCC
Rising Ocean temperatures
The Atlantic, Pacific and
Indian oceans have
warmed by 0.06 C in since
1955 (Science, 24 March
2000, pg 2225). This result
was determined by
compiling millions of
measurements of the deep
oceans made from 1948 to
1995.
More recently (Science,
13 April 2001), climate
calculations indicate that
the anthropogenic rise in
CO2 explains this sea
warming.
Coral reefs are dying all around the
world, likely as a result of the
warming of the oceans.
Increasing Melt Area on Greenland
• 2002
all-time record melt area
• Melting up to elevation of 2000 m
• 16% increase from 1979 to 2002
70 meters thinning in 5 years
Satellite-era record melt of 2002 was exceeded in 2005.
From Jim Hansen
Source: Waleed Abdalati, Goddard Space Flight Center
GREENLAND MELT
Melt descending
into a moulin,
a vertical shaft
carrying water
to ice sheet base.
Source: Roger Braithwaite,
University of Manchester (UK)
Jakobshavn Ice Stream in Greenland
Discharge from major
Greenland ice streams
is accelerating markedly.
Greenland’s largest
outlet glacier, drains
6.5% of the ice sheet.
Doubling of flow speed
from 1997 to 2003.
Complete melting
would raise sea level
by 7 meters.
Source: Prof. Konrad Steffen,
Univ. of Colorado
Melting
Polar Ice
Increasingly higher number of Polar
Bears drowning. (Science 2007)
The northeast passage is
predicted to open up in
2050, allowing ships to sail
from London to Japan along
the coast of Siberia.
Sea levels are
rising
Present predictions based
on glacial melt rates
indicate that the sea level
will rise 10-20 inches in
the next century. Rate of
rise is 0.1 inch since 1993
(NASA).
Washington
New York
Bangladesh
Beijing
Melt all of the ice sheets: 70 m increase in sea level (above scale in meters)
Global Warming?
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Earth has warmed 1° F in the last century
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The CO2 abundance has risen by 20% since 1950.
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The oceans have warmed 0.06 C since 1955.
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The sea level is rising 0.1 inches each year.
Global Warming & Society
Political Intrigue
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Good word: Orwellian: 1) of or relating to the
works by George Orwell, particularly the novel 1984,
about a future totalitarian state. 2) A policy
controlled by propoganda, misinformation and denial
of truth, and manipulation of history.
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
USA consumes 25% of the World’s Oil
USA has 4.5% of the World Population
World Energy Consumption 1995
Country
USA
France
Germany
Japan
Mexico
Brazil
India
China
Egypt
Turkey
Pop (M)
267
58
82
125
91
159
929
1,220
62
61
BTU/capita
327
147
157
142
57
25
11
27
21
33
GNP/capita
26,026
26,437
29,607
40,846
2,743
4,327
349
572
763
2,707
Kyoto
Protocol
Emission of CO2
USA
69% Oil for Transportation
92% Coal for Electricity
40% of all petroleum is expended by transportation
Canada
Venezuela
Mexico
QuickTime™ and a
decompressor
are needed to see this picture.
Saudi Arabia
Iraq
Kuwait
Associate Editor / Air Force Mag.
Kyoto Protocol
2002
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In 1997 the Kyoto Protocol was formulated.
The treaty calls for the 38 largest industrial nations to reduce
emissions due to greenhouse gases.
But the Protocol would not take effect until it is ratified by the
nations emitting at least 55% of the greenhouse gases.
In March of 2001, the USA rejected the Protocol on the grounds
that it would hurt the economy.
The USA, with 4% of the world population, produces 25% of
the greenhouse gases. The protocol would require the USA to
reduce the emissions by 7% by 2010.
In June 2002, the European Union and many other countries,
including Japan, proceeded to ratify the Protocol, without the
USA. The union of countries produce almost 55% of the
greenhouse gases.
Kyoto Protocol 2005
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Green: signed & ratified
Yellow: ratification pending
Red: signed, refused ratification
Grey: not involved
Article in Le Monde (2004)
QuickTime™ and a
decompressor
are needed to see this picture.
2005
60 Minutes interview
with Dr. James
Hansen
Paris vs
Tucson
1960 metro stops in Paris!
LONDON
Summary: Global Warming
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The CO2 abundance has risen by 20% since 1950.
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Earth’s atmosphere has warmed 1° F in the last century.
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Oceans have warmed 0.06 C since 1955
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The sea level is rising 0.1 inches each year
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If Greenland melts, the sea level will rise 7.2 m
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If Antarctic ice sheet melts the sea will rise 61 m
Sources of Information
1. Primary Sources:
1. Science http://www.sciencemag.org/
2. Nature
http://www.nature.com/nature/index.html
2. Secondary Sources:
1. Scientific American
http://www.sciam.com/
3. USA Scientists: National Academy of Sciences
1. http://www.nasonline.org/site/PageServer
4. International Panel: IPCC* (http://www.ipcc.ch/)
* Intergovernmental Panel on Climate Change (Nobel Peace Prize along with Al Gore)