Transcript The PETM and Leaf Margin Analysis

The PETM and Leaf Margin Analysis:
How does the PETM and Leaf Margin Analysis
Relate to Climate Change we are facing
today?
Erica Shook
Honors Climate Change Biology- NCSSM Online
20 December 2011
What is the PETM?
 PETM stands for Paleocene Eocene Thermal Maximum.
 The PETM was a phenomenon in Earth’s history were the
temperature jumped to high temperatures for about 10,000
years. This jump reached 6 degrees Celsius in average
temperature.
 6 degrees Celsius may not seem like much but remember
that annual temperature is a average of global temperature
so in some places the jump was more than 6 degrees.
When Was the PETM?
• Cenozoic Era is known as age
of mammals.
What caused the PETM?
 There is controversy over what caused the PETM.
 Most theories believe there was a release of a green
house gas from some kind of sink.
 As of now the leading theories include...
 A release of Methane from Methane stores deep below the
ocean’s surface.
 Volcanic eruption that released Carbon Dioxide.
 A comet impact that released Carbon Dioxide.
 …. And more!
o Some people also argue that just one of these events
would not be enough to trigger the PETM and that it
would take multiple of these events to cause it.
• In the end as of now we do not know what caused the
PETM.
Why is the PETM important?
What did the Earth look like during
the PETM?
 The Earth was virtually ice-free.
 Midwest America looked more like what coastal South Carolina
does today.
 Palm trees grew in Canada.
 Alligators even swam in Artic swamps.
Relative Position of Continents
during PETM
Leaf Margin Analysis
 Leaf margin Analysis is the
process of comparing the
amount of smoothed edged
leaves to the amount of
toothed edged leaves in a
sample by a percent.
 This percent is then put into a
linear function that has been
created from data collected of
actual samples of temperature
compared to the percent of
smooth to rough edged
leaves.
 The output of the linear
function is the average annual
temperature in Celsius of the
time and place from which the
leaves are from.
How does this method Work?
 The reason this method works is because toothed leaves
are able to begin photosynthesis earlier than smooth
edged leaves in the spring.
 However toothed leaves lead to a high amount of water
loss which does not provide adequate water to the tree in
a hot climate.
 So because of this smooth edged leaves are more likely
to be able to grow in warm climates
How does Leaf Margin Analysis
help us learn about the PETM?

In the Big Horn Basin in Wyoming fossils have
been found from the PETM.

Fossils of Plants and animals were buried by
eroded mud of the still growing Rocky Mountains
and as this mud hardened the plants and animals
fossilized.

Today millions of years later scientists have
discovered these fossils.

Scientists can sort these plant fossils by smooth
and rough edged leaves and use Leaf Margin
Analysis to estimate the temperature of the
PETM.
Lab Activity
Hypothesis: Do you believe that your group estimate or the
total class estimate will be a more accurate estimate of the
annual temperature of Hickory, NC?
Smooth VS. Rough Edged leaves
Finding Percent
We now will find the percent of smooth edged leaves to the
total collected.
Smooth Edged Leaves
Total Number of Leaves
So for example if we had 6 out of 10 smooth edged leaves
we would plug into the above formula and get…
6/10= .6
However we need a percent answer so we have to multiply
our answer by 100….
(6/10) x 100 = 60%
Calculating Temperature
Now we can plug in our percent answer in for x in the
linear function…
F(x)= 30.06x+ 1.141
Or
Y=30.06x+1.141
X=Our Percent answer
With our example of 60% we would plug .60 in for X …
Y=30.06(.60)+1.141
And Get…
Y=19.177°C
Where Y equals the estimated temperature in Celsius.
Do our results align with the actual
annual temperature?
 The actual annual temperature in Hickory, NC in 2011
was 57.6 degrees Fahrenheit or 14.223 degrees Celsius.
 Why Might our results not align?
 Sample Size
 Time collected
Leaf Margin Analysis an
Imperfect Technique?
 The process of Leaf Margin Analysis used by scientists
makes the assumption that the percent of smooth to
total leaves are relatively the same as million of years
ago.
 Do we know that Leaf Margin Analysis 100% works… no.
 We do have other evidence to support the data
concluded from leaf margin analysis from other sources.
How does the PETM relate to Climate
Change today?
PETM
Cause
Current Warming
?????
Less than 2 billion tons per
Carbon emissions year
Rate of warming 0.025°C per 100 years
Environmental
impact
Ecosystem &
human impact
Anthropogenic burning of fossil fuels (oil, coal, natural
gas, etc)
At least 30 billion tons per year
1 to 4°C per 100 years
Observed impacts: significant sea ice decline, extreme
drought, more wildfires, increase in glacier melt, more
catastrophic floods, ocean acidification, sea level rise,
shoreline erosion
Ocean circulation reversed,
oceans acidified, permafrost
melted, peatlands and forests
Potential impacts: degraded air and water quality,
burned in wildfires
permafrost melting, global ocean circulation changes,
more violent winter storms and spring tornado seasons,
more intense hurricanes
Migration of land mammals,
extinction of some benthic
foraminifera, coral bleaching
Observed impacts: Famine and malnutrition due to
drought, coral bleaching, species endangerment
Potential impacts: increased mortality from extreme
weather and malnutrition, increase in disease vectors,
decrease in agricultural yield, mass wildlife migration
and extinction, total societal collapse
How is the PETM different from
today’s Climate Change?
Works Cited
 Hickory Weather, Forecast, Temperature and Precipitation.
n.d. 2011 14 September
<http://www.clrsearch.com/Hickory_Demographics/NC/Wea
ther-Forecast-Temperature-Precipitation>.
 "Prehistoric Climate Change and Why it Matters." n.d.
Smithsonian Education. 15 December 2011
<http://www.smithsonianeducation.org/educators/lesson_pl
ans/climate_change/index.html>.
 The Energy Collective. n.d. 15 December 2011
<http://theenergycollective.com/davidlevy/55886/arguingrocks>.
 The Paleocene Eocene Thermal Maximum. n.d. 15
December 2011 <wikipedia.org>.
