By C. Kohn
Natural Resources, WUHS
VOSTOK ICE CORE DATA
T.P.S.
Whiteboards: Choose one questions to respond to:
If CO2 levels are elevated, do we know that the cause is
human-related? Does it matter?
Why should it matter if global temperatures are
increasing if they have increased in the past? Isn‟t it
normal for climatic temperatures to change?
What would happen if CO2 levels dropped back to
normal within a few years?
Have your perceptions of this issue remained the same
or have they been altered? How so?
WHATCHA KNOW?
The Vostok Ice Core Data provides us with
160,000 years of climate data.
Air is trapped in the bubbles of ice.
This air can be analyzed to determine what is
„normal‟ for the earth‟s climate.
Nothingis normal however…average temperatures
and other components fluctuate constantly.
Source: Michigan State Univ: http://www.globalchange.umich.edu/gctext/Inquiries/Inquiries_by_Unit/Unit_8a.htm
WHAT IS NORMAL?
The only thing that is “normal” about the earth‟s
climate is that it changes…a lot
Climate is a combination of many different
variables, all of which can change and all of which
are affected by other variable changes.
While this change is normal for the planet, it is not
for humans, let alone most life on the planet.
We as a species are used to little climate variation.
Most species today are not adapted to dramatic change
When adaptations are not suitable for the environment
in which they live, species will go extinct.
SEE A LOT OF MASTODONS AROUND?
Most life on earth today has adapted to the
“normal” global climate of today.
As the earth warmed after the Wisconsin Ice
Age, species either were driven to extinction
(such as mastodons) or adapted (such as
humans).
Adaptations were possible because the earth
warmed slowly.
CHANGE IS NORMAL. RAPID CHANGE ISN’T.
With slow changes, species can adapt.
With rapid changes, species will go extinct.
Why?
Think:what causes adaptations to occur?
TPS and Whiteboards
NUMBERS DON’T LIE
The air from hundreds of thousands of years is
trapped in ice.
This air is like a climatic time capsule.
By looking at what the earth was like based on
different climatic factors, we can see what kind of
earth will be created by the factors of today.
By knowing how levels of CO2, CH4, and dust
affect temperature, we can better understand
what impact be created today‟s levels of these
substances.
THE FACTORS
The factors we measure in the ice are as follows:
Carbon Dioxide (CO2) – by product of fuel consumption
(bodily and transportation); increases atmospheric heat
retention.
Methane (CH4) – results from anaerobic digestion, 21x
more potent than CO2 at heat retention
Atmospheric Dust – raises/lowers global temperatures
Deuterium (2H) – „heavy‟ version of Hydrogen; ratios of
this isotope in ice indicate global temperatures for a
given year.
CARBON DIOXIDE (CO2)
CO2 is the byproduct of cellular respiration.
When our cells break down sugars and fats for
energy, water (H2O) and carbon dioxide (CO2)
are created and expelled as we breath out.
CO2 occurs naturally in the environment and is
necessary for life on earth.
Plants use this CO2 in photosynthesis to make
more sugars, starches, and fiber.
THE ATMOSPHERE – THE GREAT EQUALIZER
CO2 also happens to „hold‟ heat in the atmosphere.
When the sun‟s rays strike the earth, they are transformed
into heat, which dissipates into space.
Our atmosphere keeps some of this heat on the surface of
the earth. This makes life possible by minimizing
temperature extremes.
Increased levels of CO2 = increased heat retention
Normally, CO2 is not a problem – it is reabsorbed by
plants and expelled by animals in a balanced fashion.
Whiteboards – show this concept visually
CARBON DIOXIDE (CO2)
In a way, CO2 is sort of like the windows on
your car. Normally, the window is open a little
so that the car gets warmer, but not too warm.
However, as CO2 levels rise, the effect is similar
to closing the windows on a car – less heat is
lost and global temperatures rise.
It‟snot that heat is „trapped‟. Rather, it‟s just not
lost as much.
Whiteboards – show this concept visually
WHICH CAUSES WHICH?
375 ppm
275 ppm
METHANE – CH4
CH4, or methane, is the „main ingredient‟ of
natural gas.
It is also released when living things
decompose or are broken down in the absence
of oxygen (such as in the stomach of a cow).
In the atmosphere, methane absorbs radiation
that would otherwise escape into space,
converting it into heat.
TPS: Create a Methane Slogan
METHANE – CH4
Methane is 21 times more powerful at warming than
carbon dioxide (CO2)
Once released remains in the atmosphere for 12 years.
Since 1750, CH4 has increased from 700 ppb to 1745
ppb, an increase of 150% due to human activities.
Methane input into the atmosphere has leveled off but
remains 2.5 times higher in concentration than it would
be without human activity.
Source: http://www.epa.gov/methane/scientific.html
CH4 LEVELS TODAY: 1750 PPB
(ABOUT AS HIGH ON THIS GRAPH AS THIS LINE!)
WB
Whiteboard: So what?
Take on the stance of “it isn‟t real” or “it
doesn‟t matter”.
How would you respond to this information?
Does this matter? Why or why not?
ATMOSPHERIC DUST
Atmospheric dust from human activity as well as
natural sources including volcanoes can alter
global climate as well.
This dust can either raise or lower temperatures.
For example, a volcano in Tambora in 1816 cause
the „year without a summer‟.
Dust can also absorb sunlight and heat up the
atmosphere.
Dust is poorly understood.
Source: Harvard University, Earlham College: http://www.earlham.edu/~ethribe/web/tambora.htm
DEUTERIUM- 2H
Deuterium is the heavier version of hydrogen.
All atoms have three parts – electrons, protons,
and neutrons.
Atoms can lose protons without becoming
different atoms.
Hydrogen can have no proton (1H) or it can
have one proton (2H).
Hydrogen with a proton is called deuterium.
DEUTERIUM
Deuterium is a heavier version of hydrogen.
Deuterium is less likely to evaporate because it
is heavier.
The colder the climate, the less deuterium is
found in ice.
The warmer the climate, the more that is found.
Slogans: Deuterium
TEMP AND GREENHOUSE GASES
This enables us to compare CO2 and CH4
levels in ice bubbles with the amount of heavy
hydrogen in that ice.
This means that we can compare how
temperatures were affected over hundreds of
thousands of years by varying CO2 and CH4
levels.
In short, we can know exactly what previous
levels of CO2 and CH4 caused for temperatures
Temp Change / ka
0
1
2
3
-4
-3
-2
-1
1
5
9
13
17
21
25
29
33
37
41
45
49
53
57
61
65
Wisconsin Ice Age
69
73
77
81
85
89
93
97
101
105
Gas Age (ka)
109
Temp Rate of Change
113
117
121
125
129
133
137
141
145
149
153
157
161
165
169
VOSTOK DATA – TEMP CHANGE RATES
173
177
181
185
189
193
SUMMARY
We know that CO2 and CH4 are greenhouse gases –
more heat is retained in the atmosphere when their
levels are elevated.
We know that CO2 and CH4 are dramatically higher than
normal
CO2 – previous 400,000 yr high: <300 ppm
CO2 Today: 375-400 ppm and increasing
CH4 levels are 2.5x greater than the 400,000 yr average
and double their previous high 150,000 yrs ago.
A warming planet further increases the levels of CO2
and CH4 in the atmosphere (oceans can hold less at
inc. temps)
SUMMARY
We know that temperatures will rise 2-5o C
globally.
We know that previous climate extremes were
between +/- 3o C
ice ages result from drops of several degrees
i.e.
Imagine what a 5o increase would do!
We know that human activity has caused the
dramatic increase in CO2 and CH4.
SUMMARY
We know that the earth naturally warms and
cools.
However, we also know that the earth does not
naturally warm and cool at this fast of a pace
Natural mechanisms for species adaptations
cannot change at the rate at which the planet
is changing.
Species will go extinct!
SO…
So we know that human activity has increased
CO2 and CH4 levels
And we know that CO2 and CH4 increase global
temperatures by absorbing solar radiation
And we know that the earth is warming on
average, and the our warmest years on record
have been the almost all of those in the past
decade.
So…is it possible for this not to be human caused?
EVERYTHING ELSE ASIDE…
Even if humans weren‟t to blame, even if the
earth wasn‟t warming, and even if this was
natural, it wouldn‟t change one simple
undeniable fact:
There are extraordinarily high levels of
greenhouse gases in the atmosphere.
FINAL WORD
There are extraordinarily high levels of
greenhouse gases in the atmosphere.
If the earth hasn‟t already warmed from them,
it will soon.
Regardless of how they got there, they will
cause problems.
Species will go extinct. Natural cycles as we
understand them will change. Humans will be
affected.
SO WHAT DO WE DO?
We must lower the levels of greenhouse gases in
the environment. But…
How do you get rid of something you can‟t see?
What can anyone do? Why should anyone do it?
Whiteboard