CHM 110 - CHEMISTRY AND ISSUES IN THE ENVIRONMENT
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ISSUE #1
SHOULD THE NATIONS OF THE WORLD COMMIT TO SPECIFIC GOALS FOR THE REDUCTION
OF GREENHOUSE GASES?
C. Ophardt, Professor of Chemistry, Elmhurst College; Elmhurst, Illinois
Copyright 1997
Table of Contents:
PART I: EVIDENCE FOR GLOBAL WARMING
PART II. GREENHOUSE VISUALIZER
PART III. GLOBAL CLIMATE WARMING DEBATE
For the Spring Term 1998: Parts I and III are to be done for the initial Issue # 1 Discussion.
Part I is to be turned in for grading (3 pts) and is separate from the main discussion in Part III. (7 pts)
Part II will be done in conjuction with Lab # 3.
This issue is available in hard copy in the CHM 110 Manual.
See General Course Info for instructions about
On-Line Discussion Format
See General Course Info for instructions
to download the Brief Issue Report text files.
See General Course Info for instructions
to submit the files for grading.
PART I: EVIDENCE FOR GLOBAL WARMING
Materials for Part I were prepared using data and information from the following
WWW web sites:
http://www.covis.nwu.edu/globalWarming/global.html
CoVis Interschool Activity - Global Warming Doug Gordin
http://www.antdiv.gov.au/aad/sci/glacio/issues_glacio/issues_glacio.html
Dr. T.H. Jacka, Glaciology Program, Antarctic Cooperative Research Centre
and Australian Antarctic Division
Objective: To determine whether global warming is just
"natural variation" or whether the pattern is influenced by human
activities.
A. ANALYZE THE PAST 150 YEARS OF TEMPERATURE DATA
This exercise investigates the variation in global temperatures over the
past 150
years. The temperature values in the data set are provided as differences
from a mean of 15 degrees C. These data have been analyzed by scientists
to show a 0.5 degrees C increase in global temperatures. However, this finding
is under dispute because some claim that the amount of error in the data
is too large to justify the conclusion. This data set has been created using
the following steps:
o Data was collected from land based stations, from ocean buoys, and from
ships.
o For each year data has been averaged to come up with a yearly average.
o Data is smoothed to accommodate historical changes that skew the data
(e.g., weather stations near cities record artificially high temperatures
because create what is called an "urban heat island effect.").
Brief report form Part I (text file)
QUES. 1: a. Use a ruler or straight edge to draw a "best
straight line" through the data for Figure
1. State a generalization that incorporates time and temperature that
interprets this data.
b. What is the approximate temperature change from 1850 to the present?
B. AVERAGE GLOBAL TEMPERATURES FROM ICE CORES
Antarctica is the coldest, windiest, highest and driest continent on Earth.
The annual precipitation of snow, averaged across the continent, is about
30 centimeters. Because of the low temperatures, however, there is little
or no melt. Thus the snow has accumulated year after year for thousands
of years and, with time, is compressed to ice to form the Antarctic ice
sheet, which is on average about 2,500 meters thick.
Since the ice sheet is formed by the accumulation of snow year after year,
by drilling from the surface down through the ice sheet, we drill our way
back in time. Ice drills are designed to collect a core as they cut through
the ice, so samples are collected that are made up of ice deposited many
thousands of years ago.
As the snow is deposited on top of the ice sheet each year, it traps different
chemicals and impurities which are dissolved in the ice. The ice and impurities
hold information about the Earth's environment and climate at the time of
deposition. The Soviet Union drilling project at the Vostok Station in Antarctica
has yielded over a mile of ice cores formed from the snows over the past
160,000 years.
Ice Core Dating
By sampling at very fine intervals down the ice core, and provided that
each annual layer of snow is thick enough, several samples from each year
may be measured for the different chemical properties. These include airborne
continental dust and biological material, volcanic debris, sea salts which
are deposited on the ice sheet surface along with the snow, thus mixing
with the snow and also acting as a distinctive barrier between different
ice layers.
The graphical correlation of ice core depth versus time is shown in Figure 2.
Historic Global Temperatures
The isotopic composition of water, and in particular the concentration
of the heavy isotope of oxygen, O-18, relative to O-16, is indicative of
the temperatures of the environment. During warm periods, the concentration
of the slightly more nonvolatile O-18 in the ice is lower than during cold
periods. This reflects the lower concentration of O-18 in the atmosphere
available for condensation into snow during warm periods due to little evaporation
of O-18 from the oceans.
A record of temperature variations over the last 160,000 years, shown in
Figure 3, has recently been constructed
by analyzing the O-18 to O-16 ratio in the Vostok ice core. The numbers
in this data set are recorded as differences from the current average temperature
(15 degrees C).
Starting on the left-hand side of the graph at about 140,000 years ago,
the climate was about 6 C colder than it is today - an ice age period. Then
at about 130,000 years ago, there was a quite rapid warming period until
about 125,000 years ago, when the climate was, perhaps, 1 C or 2 C warmer
than today - an inter-glacial period. From 120,000 to about 20,000 years
ago, there was a long period of cooling temperatures, known as the last
Great Ice Age. From about 18,000 or 19,000 years ago to about 15,000 years
ago, the climate went through another warming period to the next inter-glacial,
- the one we are now in.
QUES. 2: What are the maximum and minimum temperatures
(in degrees Celsius) reached during the last 160,000 years? First find differences,
then find the actual temperatures.
QUES. 3: What was the predominate type of climate during
the past 165,000 years?
QUES. 4 : The amount of temperature change usually discussed
in the global warming controversy seems very small. Typically, changes of
around 3 degrees C are discussed. Based upon Figure
3, why are temperature changes this small important?
Carbon Dioxide
The snow near the surface of the ice sheet is like a sponge with channels
of air between the snow grains. As more and more snow is accumulated on
top, the underlying snow is compressed into ice and the air forms bubbles
in the ice. Ice cores therefore can be analyzed not just for the chemical
and physical properties of the ice, but also for the properties of the air
trapped in the ice. These bubbles are actual samples of the atmosphere from
thousands of years ago. Concentrations of carbon dioxide measured in the
air bubbles trapped in the ice are shown in Figure
4.
QUES. 5: a. Correlate and discuss similarities and differences
(look at peaks and valleys) in the the overall shapes of the carbon dioxide
curve with the curve for temperature versus time? Be specific in relating
concentration of carbon dioxide as a predictor of temperature.
Antarctic ice core from Law Dome near Australia's Casey Station. Figure 5.
Concentration of Carbon Dioxide from trapped air measurements for the DE08
ice core near the summit of Law Dome, Antarctica. (Data measured by CSIRO
Division of Atmospheric Research from ice cores supplied by Australian Antarctic
Division). Dr. T.H. Jacka, Glaciology Program,Antarctic Cooperative Research
Centre and Australian Antarctic Division.
A closer look at the carbon dioxide changes within the last thousand years
can be seen in Figure 5. The concentrations of carbon dioxide in the atmosphere,
were measured in the bubbles from an Antarctic ice core from Law Dome near
Australia's Casey Station. The Law Dome ice core is at a location where
the snow accumulation is much higher than at Vostok. Thus, the time scale
for the Law Dome core is expanded and it can provide us with more detailed
information about recent climate changes, though it can not go back in time
as far as the deeper Vostok ice core.
QUES. 6: a. Explain what is significant about the change
in carbon dioxide concentration with time as viewed in Figure
5.
b. What energy consuming and carbon dioxide producing events were taking
place in most of the Northern Hemisphere at the time that of the dramatic
increase in the carbon dioxide concentration?
C. MAUNA LOA CARBON DIOXIDE RECORD
Mauna Loa is a mountain on the island of Hawaii. The data collected at Mauna
Loa has demonstrated conclusively that the amount of carbon-dioxide (CO2)
in the atmosphere is rising rapidly. Carbon dioxide is an invisible gas
that is harmless to humans. In fact, we breathe out carbon dioxide every
time we breath. Both carbon dioxide and carbon monoxide are produced by
burning fossil fuels (gas, coal,and oil).
The Mauna Loa data set, Figure 6, is the
largest continuous record, 35 years, in existence of atmospheric carbon-dioxide.
Unfortunately, this is still a very short time on the scale that climate
is often studied, which can span thousands of years. One of the most arresting
facts about the data is how fast the levels of CO2 is climbing. The speed
or rate of change is widely believed to unparalleled in the history of the
earth.
QUES. 7: Calculate the net rate of increase per year in
CO2 from the initial time to end of the time period. What are the units
of your rate estimate?
rate = (CO2 conc. end - CO2 conc. initial)
(end time - initial time)
QUES. 8 : The burning of fossil fuels in combustion reactions
results in the production of carbon dioxide. Compare Figure 6 and Figure 7 to draw a possible conclusion about a
correlation between the increasing concentration of carbon dioxide in the
atmosphere and the use of fossil fuels in electric power plants, industrial
plants, commercial and residential properties, trains, trucks, and automobiles.
QUES. 9: Based upon ALL of the data presented, has there been an
"unnatural" variation or a variation caused by human actions in
the atmospheric concentration of carbon dioxide, which has resulted in an
increase in global warming, since the industrial revolution? Summarize the
arguments in favor of either a YES or NO answer.
PART II. GREENHOUSE VISUALIZER
This part of the issue should be completed with the aid of the Greenhouse
Visualizer found at: http://www.covis.nwu.edu/gev.cgi
Energy from the sun provides the heat for the earth's surface and atmosphere.
The energy provided by the sun to the earth each day must be in balance
with the energy that is radiated back into space from the earth. A hot "body"
such as the sun emits radiation in the short wave region (U.V. and visible),
while the earth a cooler "body" emits radiation in the long wave
region (infrared, IR).
The purpose of this investigation is to use data from satellites to understand
the various energy relationships of the earth and its atmosphere. In the
process a greater understanding of the greenhouse effect will be achieved.
The energy from the sun called "insolation" contains ultraviolet
and visible light. The majority of the U.V. light is absorbed by the ozone
layer and heats the atmosphere, as a consequence the majority of the solar
output that reaches the earth's surface, and is absorbed, is in the form
of short wave radiation of visible light. The measurements are made by satellite
above the atmosphere. If no other effects are operating, the surface of
the earth should have an average temperature of -18 degrees C.
A significant portion of the incoming solar radiation is immediately
reflected back into space by clouds, ice, snow, sand, water, and other reflecting
surfaces. Shortwave Reflectancemeasures the amount of the sun's energy that
is reflected due to the albedo of Earth-Atmosphere system. Short wave radiation
is measured in watts per meter squared. The measurements are made by satellite
above the atmosphere.
SHORTWAVE ABSORPTION:
On the average about 50% of the incoming solar radiation is absorbed by
the earth surface, while another 20% is absorbed by the clouds and gases
such as ozone in the atmosphere.
Surface Temperature provides a measure of the temperature all over the Earth. The temperatures are measured in Kelvin. To convert to Celsius temperature subtract 273 from the Kelvin temperature. The heat at the surface is translated into long wave radiation.
Outgoing Longwave Terrestrial Emission (also called longwave radiation) measures the amount of energy leaving the Earth arising from the Earth's surface temperature. Longwave emissions of energy are in the thermal infrared, IR, region of the spectrum. This IR energy is in the form of heat, analogous to the heat from a hot electric burner on a stove.
Greenhouse Effect is the amount of energy retained by the Earth's atmosphere.
The natural Greenhouse Effect is not a bad or unusual thing, and is absolutely
necessary for maintaining life on Earth. However, if the amount of energy
stored in the atmosphere increases, it could cause the average temperature
of the earth to increase as well -- this is called global warming and could
have significant effects on earth's basic climate and agricultural cycles.
The Greenhouse Effect Energy stored in the atmosphere is calculated by computing
how much radiation is on average produced by the surface temperature (using
a conversion method called the black body model) and then subtracting the
amount that leaves the atmosphere (i.e. the outgoing long wave radiation).
The difference is the Greenhouse Effect Energy being retained in the atmosphere
measured in watts per meter squared.
As the IR energy is emitted from the earth's surface, only a small fraction
of the energy actually escapes to outer space. Two major molecules, water
and carbon dioxide temporarily absorb specific wavelengths of IR radiation
that correspond to the energy required to bend the molecules. Shortly, the
vibrationally excited molecules lose their energy either by colliding with
other molecules and heating up their surroundings, or by remitting the radiation.
Either process occurs in all directions, half of the energy flows upwards
toward outer space, while half flows back to the surface and further heats
the surface and the atmosphere. This process is known as the natural greenhouse
effect and results in the average surface temperature of +15 degrees C rather
than -18 C. This natural greenhouse effect makes the earth habitable. As
a comparison, Venus has a much higher concentration of carbon dioxide, an
extreme greenhouse effect with surface temperatures of as high as 800 degrees
F. On the other hand, Mars with little atmosphere and virtually no gaseous
carbon dioxide has temperatures that vary from 80 during the day to -100
degrees F at night.
Greenhouse Percent measures the amount of energy stored in the atmosphere.
So, its quite similar to the Greenhouse Effect Energy. However, it shows
the Greenhouse Effect as a fraction of the total possible energy that could
be stored in the atmosphere, rather than as an amount. This way of measuring
the Greenhouse Effect is useful for detecting changes in it over time, since
it measures it as an absolute number, thus providing easy comparison between
different months or years.
PROCEDURE TO USE THE GREENHOUSE EFFECT VISUALIZER
The visualizations can be obtained through the World Wide Web at:
http://www.covis.nwu.edu/gev.cgi
For each visualization, you must select three control parameters: The global
effect, the time period, and the resolution. If you forget to set one of
these, it will use a default value that may not be the one of current interest.
The maps will load on the top of the control parameter section, with the
most recent map at the top. Use the right hand scroll bar to move down the
page. After a certain series of maps are analyzed, there is a button to
reset the page to back to blank.
TEMPERATURE AND MAP RESOLUTION:
Just like maps, some visualizations are very detailed while others provide
a much more general "averaged" view. The level of detail provided
by a visualization is called its resolution. The resolution is described
by how many degrees of latitude and longitude are covered by a single averaged
number.
Brief report form Part II (text file)
QUES. 10: Start out by looking at the same variable at
different resolutions. For example, look at January surface temperature
at the highest resolution at 2.5 degrees per square. Give the coldest and
warmest temperatures and general location. To get an accurate number click
on the map, after a short period the map is redrawn with a line on the bottom
indicating an exact number for the location clicked.
Coldest ________________ Warmest ________________
b. Look at January surface temperature at the lowest resolution at 180 x
360 degrees for January. The lowest resolution gives a single average temperature
for the whole world, what is it? ________.
TOTAL RADIATION BUDGET
The earth not only absorbs energy from the sun it also has to give it off
energy by retransmitting it. This energy balance is called maintaining the
earth's radiation budget. At different parts of the year some portions of
the earth absorb more heat than they give off whereas other places give
off more heat than they absorb.
These next visualizations show the radiation budget for the earth as a whole
using the low resolution of 180x360 to give the global
single averages. Use March for these determinations and
report the values obtained.
A. Insolation (180x360 - March) - The radiation comes from
the sun to earth in the form of sunlight. _______
B. Shortwave reflectance (180x360 - March) - The sunlight
that is reflected is called short wave reflected radiation. This radiation
does not affect processes on earth, since it is never absorbed. Therefore,
reflected sunlight does not cause anything to heat up. ________
C. Shortwave absorption (180x360 - March) - The sunlight
that is not reflected is absorbed by the earth- atmosphere system. _____
QUES. 11: What percentage of the sunlight is reflected; and percent
absorbed compared to the total insolation?
D. Outgoing Longwave Terrestrial Emission (180x360 - March)
measures the amount of energy leaving the Earth arising from the Earth's
surface temperature; also called terrestrial radiation or emission. _____
E. Greenhouse Effec t (180x360 - March) - Substantial amounts
of energy are stored in the earth's atmosphere. The amount and location
of this energy also varies with the seasons. _______
The Greenhouse Effect Energy stored in the atmosphere is calculated by computing
how much radiation is on average produced by the surface temperature (using
a conversion method called the black body model) and then subtracting the
amount that leaves the atmosphere (i.e. the outgoing long wave radiation).
The difference is the Greenhouse Effect Energy being retained in the atmosphere
measured in watts per meter squared.
F. Percent Greenhouse Effect (180x360 - March) - Shows
the Greenhouse Effect as a fraction of possible energy that is stored in
the atmosphere compared to the total outgoing energy produced by the earth
as a black body. _____
G. Comparison of Percent Greenhouse Effect (180x360) Compare
the months of January, July, and September to that of March. Differences,
comments.
PART III. GLOBAL CLIMATE WARMING DEBATE
The final part of this exercise is the "Global Warming Debate
", where you will use the information and concepts from all the sources
to engage other students in a general debate. The instructor will divide
the class into groups for the debate. The groups should eventually reach
a consensus on one of the the options listed below.
The "United Nations Framework Convention on Climate Change" was
adopted by a large number of nations at the 1992 "Earth Summit"
in Rio de Janeiro.
General reference:
The United Nations Framework Convention on Climate Change
At this time firm targets and timetables were not been firmly established.
Since then various groups have continued to work on the implementation of
the "Convention". In 1997, a new effort in Koyto, Japan will be
made according to the principles of a Ministerial Declaration agreed to
in 1996. Parts are quoted as follows:
"The Ministers and other heads of delegations present at the second
session of the Conference of the Parties to the United Nations Framework
Convention on Climate Change, ... is a demonstration of our intention to
continue to take an active and constructive role in addressing the threat
of climate change,
2. ...endorse the Second Assessment Report of the IPCC as currently the
most comprehensive and authoritative assessment of the science of climate
change, its impacts and response options now available. ....should provide
a scientific basis for urgently strengthening action at the global, regional
and national levels, ... to limit and reduce emissions of greenhouse gases,
and for all Parties to support the development of a Protocol; and note the
findings of the IPCC, in particular the following:
- The balance of evidence suggests a discernible human influence on global
climate. Without specific policies to mitigate climate change, the global
average surface temperature relative to 1990 is projected to increase by
about 2 C (between 1 C and 3.5 C) by 2100; average sea level is projected
to rise by about 50 centimeters (between 15 and 95 centimeters) above present
levels by 2100. Stabilization of atmospheric concentrations at twice preindustrial
levels will eventually require global emissions to be less than 50 per cent
of current levels;
- The projected changes in climate will result in significant, often adverse,
impacts on many ecological systems and socioeconomic sectors, including
food supply and water resources, and on human health. In some cases, the
impacts are potentially irreversible; developing countries and small island
countries are typically more vulnerable to climate change;
- Significant reductions in net greenhouse gas emissions are technically
possible and economically feasible by utilizing an array of technology policy
measures that accelerate technology development, diffusion and transfer;
and significant no regrets opportunities are available in most countries
to reduce net greenhouse gas emissions;
8. Instruct their representatives to accelerate negotiations on the text
of a legally-binding protocol or another legal instrument to be completed
in due time ...regarding:
* policies and measures including, as appropriate, regarding energy, transport,
industry, agriculture, forestry, waste management, economic instruments,
institutions and mechanisms;
*quantified legally-binding objectives for emission limitations and significant
overall reductions within specified timeframes, such as 2005, 2010, 2020,
with respect to their anthropogenic emissions by sources and removals by
sinks of greenhouse gases not controlled by the Montreal Protocol;"
Kyoto
Compromise - the latest agreements reached in December of 1997
DEBATE QUESTION: Should the nations of the world agree to quantified legally-binding
objectives for greenhouse gas emission limitations and significant overall
reductions within specified timeframes?
Option # 1: Yes. Establish an international agreement on
a long term goal for stabilizing greenhouse gas emissions in the atmosphere
at a level that minimizes the risks to the biosphere and to human societies,
with a specific commitment to stabilize carbon dioxide emissions at 1990
levels by the year 2010.
If you endorse this position, make some recommendations about how to reduce
the use of fossil fuels.
Option # 2: No. No action is needed because the
"theory" of global warming caused by the burning of fossil fuels,
is an unsupported assumption. Continued research is necessary, before any
costly counter measures are implemented.
Various theoretical climate models used to predict future warming can not
be relied upon and are not validated by existing climate record.
Assignments for the Debate:
YES |
NO |
| Students B - DiBeasi | Students DiStefano -K |
| Students L-P | Students S-V |
On-Line Discussion Response
You might look at p. 113 in the lab book to help focus your thoughts and
see a format that will become more important for issues 4-6. It is not necessary
to do pages 110 and 112 in the lab manual. This is from another computer
program in the labs at Elmhurst College.
Climate
Change Information Kit- the Climate Change Convention
Grappling
with Greenhouse: Understanding the science of climate change
by the National Greenhouse Advisory Committee
Department of the Arts, Sport, the Environment and Territories, Australia
This is a very complete article and includes a few graphics and glossary
of terms. This article alone would be sufficient for engaging in debate.
Index to Climate Change
Fact Sheets from United Nations Environment Programme (UNEP). This is
an extensive collection of short fact sheets on a variety of topics.
Global Climate Change
Information Programme - comprehensive series of short essays.
Global Warming:
Myth vs. Facts, Envrironmental Defense Fund Pro side
GLOBAL WARMING HOT AIR:
SOME POPULAR MYTHS DISPELLED -pro
Myths of Global Warming National Center for Policy Analysis -Brief Analysis more on the pro side
Global Warming Alert:
A Primer on the Issue
Climate Models:
How Reliable are their Predictions? A comprehensive look at how models
are constructed, used, and an evaluation of the predictions made from these
models.
Kyoto
Compromise - the latest agreements reached in December of 1997. Look
also at some of the Newspaper articles on the bottom of the page as they
give some pros and cons.
Sites that have more of a NO side slant:
Challenges for Policy Makers
- the NO side might find something useful here
Science Has Spoken:
Global Warming Is a Myth, The Wall Street Journal, Thursday, December
4, 1997, By ARTHUR B. ROBINSON and ZACHARY W. ROBINSON
Global Climate - contains some skeptics links
Still Waiting for Greenhouse A Lukewarm View of Global Warming by - John L. Daly
World Climate Report gives contrary views on global warming. Look at the Current Features section to get a long list of articles from past issues. Might be slow in loading.
