A
Brief History of Ice Ages and Warming
Global
warming started long before the "Industrial Revolution" and the invention of the internal combustion engine. Global
warming began 18,000 years ago as the earth started warming its way out of the Pleistocene Ice Age-- a time
when much of North America, Europe, and Asia lay buried beneath great sheets of glacial ice.
Earth's climate and
the biosphere have been in constant flux, dominated by ice ages and glaciers for the past several million
years. We are currently enjoying a temporary reprieve from the deep freeze.
Approximately every 100,000 years
Earth's climate warms up temporarily. These warm periods, called interglacial periods, appear to last
approximately 15,000 to 20,000 years before regressing back to a cold ice age climate. At year 18,000 and counting
our current interglacial vacation from the Ice Age is much nearer its end than its beginning.
Global warming during
Earth's current interglacial warm period has greatly altered our environment and the distribution and
diversity of all life. For
example:
Approximately 15,000
years ago the earth had warmed sufficiently to halt the advance of glaciers, and sea levels worldwide began to
rise.
By 8,000 years ago the land
bridge across the Bering Strait was drowned, cutting off the migration of men and animals to North
America.
Since the end of the Ice Age,
Earth's temperature has risen approximately 16 degrees F and
sea levels have risen a total of
300 feet! Forests have returned where once there was only ice.
Over the past 750,000
years of Earth's history, Ice Ages have occurred at regular intervals, of approximately 100,000 years
each.
Courtesy of Illinois State
Museum
During ice ages our planet is cold, dry, and inhospitable--
supporting few forests but plenty of glaciers and deserts. Like a spread of collosal bulldozers,
glaciers have scraped and pulverized vast stretches of Earth's surface and completely destroyed entire regional
ecosystems not once, but several times. During Ice Ages winters were longer and more severe and ice sheets grew to
tremendous size, accumulating to thicknesses of up to 8,000 feet!. They moved slowly from higher elevations to
lower-- driven by gravity and their tremendous weight. They left in their wake altered river courses, flattened
landscapes, and along the margins of their farthest advance, great piles of glacial debris.
During the last 3
million years glaciers have at one time or another covered about 29% of Earth's land surface or about 17.14
million square miles
(44.38 million sq.
km.) . What did not lay beneath ice was a largely cold and desolate desert landscape, due in large
part to the colder, less-humid atmospheric conditions that prevailed.
During the Ice Age summers were short and
winters were brutal. Animal life and especially plant life had a very tough time of it. Thanks to global warming,
that has all now changed, at least temporarily.
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The World 18,000 Years Ago
Before "global
warming" started 18,000 years ago most of the earth was a frozen and arid wasteland. Over half of earth 's surface
was covered by glaciersor extreme
desert. Forests were rare.
Not a very fun place to
live.
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Our Present World
"Global warming" over the last
15,000 years has changed our world from an ice box to a garden. Today extreme
deserts and glaciers have largely given way to grasslands, woodlands, and
forests.
Wish it could last forever, but . . . .
In the 1970s concerned environmentalists like Stephen Schneider of
the National Center for Atmospheric Research in Boulder, Colorado feared a return to another ice age due to
manmade atmospheric pollution blocking out the sun.
Since about 1940 the global climate did in fact appear
to be cooling. Then a funny thing happened-- sometime in the late 1970s temperature declines slowed to a halt and
ground-based recording stations during the 1980s and 1990s began reading small but steady increases in near-surface
temperatures. Fears of "global cooling" then changed suddenly to
"global warming,"-- the cited cause:
manmade atmospheric pollution causing a
runaway greenhouse effect.
What does geologic history have to
offer in sorting through the confusion?
Quite a bit, actually.
"If 'ice age' is used
to refer to long, generally cool, intervals during which glaciers advance and retreat, we are still in one today.
Our modern climate represents a very short, warm period between glacial advances."
Illinois State
Museum
[SIZE=+3]P[/SI
ZE]eriods of Earth warming and cooling occur in cycles. This is well understood, as is the fact that small-scale
cycles of about 40 years exist within larger-scale cycles of 400 years, which in turn exist inside still larger
scale cycles of 20,000 years, and so
on.
Example
of regional variations in surface air temperature for the last 1000 years, estimated from a variety of sources,
including temperature-sensitive tree growth indices and written records of various kinds, largely from western
Europe and eastern North America. Shown are changes in regional temperature in ° C, from the baseline value for
1900. Compiled by R. S. Bradley and J. A. Eddy based on J. T. Houghton et al., Climate Change: The IPCC Assessment,
Cambridge UniversityPress, Cambridge, 1990 and published in EarthQuest, vol 5, no 1, 1991. Courtesy of Thomas
Crowley, Remembrance of Things Past:
Greenhouse Lessons from the Geologic
Record
Earth's climate was in a cool period from A.D. 1400 to about A.D. 1860, dubbed
the "
Little Ice Age." This period was characterized by harsh winters, shorter growing
seasons, and a drier climate. The decline in global temperatures was a modest 1/2° C, but the effects of this
global cooling cycle were more pronounced in the higher latitudes. The Little Ice Age has been blamed for a host of
human suffering including crop failures like the "Irish Potato Famine" and the demise of the
medieval Viking colonies in
Greenland.
Today we enjoy global temperatures which have warmed back to levels of the so called
"
Medieval Warm Period," which existed from approximately A.D. 1000 to A.D.
1350.
"...the Earth was
evidently coming out of a relatively cold period in the 1800s so that warming in the past century may be part of
this natural
recovery."
Dr.
John R. Christy
(leading climate and atmospheric science expert- U. of Alabama
in Huntsville)
(5)
[
COLOR=#470d05]G[/COLOR]lobal warming alarmists maintain that global temperatures have increased since
about A.D. 1860 to the present as the result of the so-called "
Industrial
Revolution,"-- caused by releases of large amounts of
greenhouse gases (principally carbon
dioxide) from manmade sources into the atmosphere causing a runaway "
Greenhouse
Effect."
Was man really responsible for pulling the Earth out of the Little Ice Age with his industrial
pollution? If so, this may be one of the greatest unheralded achievements of the Industrial Age!
Unfortunately, we
tend to overestimate our actual impact on the planet. In this case the magnitude of the gas emissions involved, even
by the most aggressive estimates of atmospheric warming by greenhouse gases, is inadequate to account for the
magnitude of temperature increases. So what causes the up and down cycles of global climate change?
Causes of Global Climate
Change
Climate change is controlled primarily by
cyclical eccentricities in Earth's rotation and orbit, as well as
variations in the sun's energy output.
"Greenhouse
gases" in Earth's atmosphere also influence Earth's temperature, but in a much smaller way. Human
additions to total greenhouse gases play a still smaller role, contributing about
0.2% - 0.3% to Earth's
greenhouse effect.
Major Causes of Global Temperature
Shifts
(1) Astronomical Causes
(2) Atmospheric
Causes
- Heat retention: Due to atmospheric gases, mostly gaseous water
vapor (not droplets), also carbon dioxide, methane, and a few other miscellaneous gases-- the
"greenhouse effect" - Solar reflectivity: Due to
white clouds, volcanic dust, polar ice caps
(3) Tectonic
Causes
- Landmass distribution: Shifting continents
(continental drift) causing changes in circulatory patterns of ocean currents. It
seems that whenever there is a large land mass at one of the Earth's poles, either the north pole or south pole,
there are ice ages. - Undersea ridge activity: "Sea floor
spreading" (associated with continental drift) causing variations in ocean displacement.
Playing with
Numbers
Global climate and temperature cycles are the result of
a complex interplay between a variety of causes. Because these cycles and events overlap, sometimes compounding one
another, sometimes canceling one another out, it is inaccurate to imply a statistically significant trend in climate
or temperature patterns from just a few years or a few decades of data.
Unfortunately, a lot of disinformation
about where Earth's climate is heading is being propagated by "scientists" who use improper statistical methods,
short-term temperature trends, or faulty computer models to make analytical and anecdotal projections about the
significance of man-made influences to Earth's climate.
During the last 100 years there have been
two general cycles of warming and cooling recorded in the U.S. We are currently in the
second warming cycle. Overall, U.S. temperaturesshow
no significant warming trend over the last
100 years (1). This has been well - established but not well -
publicized.
Each year
Government press releases declare the previous year to be the "hottest year on record."
The UN's executive summary on climate
change, issued in January 2001, insists that the 20th century was the warmest in the last millennium.
The news media distribute these stories and people generally believed them to be true. However, as most
climatologists know, these reports generally are founded on ground-based temperature readings, which are misleading.
The more meaningful and precise orbiting satellite data for the same period (which are generally not cited by the
press) have year after year showed little or no warming.
Dr. Patrick Michaels has demonstrated this effect is a
common problem with ground- based recording stations, many of which originally were located in predominantly rural
areas, but over time have suffered background bias due to urban sprawl and the encroachment of concrete and asphalt
( the
"urban heat island
effect"). The result has been an upward distortion of increases in ground temperature over time(2).
Satellite measurements are not limited in this way, and are accurate to within 0.1° C. They are widely
recognized by scientists as the most accurate data available.
Significantly, global temperature
readings from orbiting satellites show no significant warming in the 18 years they have been continuously recording
and returning data (1).
A Matter of
Opinion
Has manmade pollution in the form of carbon
dioxide (CO2) and other gases caused a runaway Greenhouse Effect and Global Warming?
Before joining the mantra,
consider the
following:
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Compiled by R.S. Bradley and J.A. Eddy based on J.T. Houghton et
al., Climate Change: The IPCC Assessment, Cambridge University Press, Cambridge, 1990 and published in EarthQuest,
vo. 1, 1991. Courtesy of Thomas Crowley,
Remembrance of Things Past:
Greenhouse Lessons from the Geologic Record1. The
idea that man-made pollution is responsible for global warming is not supported by historical fact. The period known
as the
Holocene Maximum is a good example-- so-named because it was the hottest period in human history. The
interesting thing is this period occurred approximately 7500 to 4000 years B.P. (before present)-- long before
humans invented industrial pollution.
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Figure 1
2. CO2 in our
atmosphere has been increasing steadily for the last 18,000 years-- long before humans invented smokestacks (
Figure 1).
Unless you count campfires and intestinal gas, man played no role in the
pre-industrial increases.
As illustrated in this chart of
Ice Core data from the
Soviet Station Vostok in
Antarctica, CO2 concentrations in earth's atmosphere move with temperature. Both temperatures and
CO2 have been steadily increasing for 18,000 years. Ignoring these 18,000 years of data "global warming activists"
contend recent increases in atmospheric CO2 are unnatural and are the result of only 200 years or so of human
pollution causing a runaway greenhouse effect.
Incidentally, earth's temperature and CO2 levels today have reached
levels similar to a previous interglacial cycle of 120,000 - 140,000 years ago. From beginning to end this cycle
lasted about 20,000 years. This is known as the
Eemian Interglacial Period and the earth returned to a
full-fledged
ice age immediately afterward.
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Figure
2
3. Total human contributions to greenhouse
gases account for only about 0.28% of the "greenhouse effect" (
Figure 2).
Anthropogenic (man-made) carbon dioxide
(CO2) comprises about 0.117% of this total, and man-made sources of other gases ( methane, nitrous oxide (NOX),
other misc. gases) contributes another 0.163% .
Approximately 99.72% of the "greenhouse effect" is
due to natural causes -- mostly water vapor and traces of other gases, which we can do nothing at all about.
Eliminating human activity altogether would have little impact on climate change.
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Figure
3
4.If global
warming is caused by CO2 in the atmosphere then does CO2 also cause increased sun activity too?
This
chart adapted after Nigel Calder (6) illustrates that variations insun
activity are generally proportional to both variations in atmospheric
CO2and atmospheric
temperature (Figure 3).
Put another way, rising Earth
temperatures and increasing CO2 may be
"effects" and our own sun the
"cause".
FU[COLOR=#00
00a0]N[/COLOR]
FAC[/CO
LOR]TS about CARBON
DIOXIDE
Of the 186 billion
tons of CO2 that enter earth's atmosphere each year from all sources, only 6 billion tons are from human activity.
Approximately 90 billion tons come from biologic activity in earth's oceans and another 90 billion tons from such
sources as volcanoes and decaying land
plants.
At 368 parts per million CO2 is
a minor constituent of earth's atmosphere--
less than 4/100ths of 1% of all gases
present. Compared to former geologic times, earth's current atmosphere is
CO2-
impoverished.
CO2 is
odorless, colorless, and tasteless. Plants absorb CO2 and emit oxygen as a waste product. Humans and animals breathe
oxygen and emit CO2 as a waste product. Carbon dioxide is a nutrient, not a pollutant, and all life-- plants and
animals alike-- benefit from more of it. All life on earth is carbon-based and CO2 is an essential ingredient. When
plant-growers want to stimulate plant growth, they introduce more carbon
dioxide.
CO2 that goes into the
atmosphere does not stay there but is continually recycled by terrestrial plant life and earth's oceans-- the great
retirement home for most terrestrial carbon dioxide.
If we are in a
global warming crisis today, even the most aggressive and costly proposals for limiting industrial carbon dioxide
emissions would have a negligible effect on global
climate!
The case for a "greenhouse
problem" is made by environmentalists, news anchormen , and special interests who make inaccurate and misleading
statements about global warming and climate change. Even though people may be skeptical of such rhetoric initially,
after awhile people start believing it must be true because we hear it so
often.
"We have to offer
up scary scenarios, make simplified, dramatic statements, and make little mention of any doubts we may have. Each of
us has to decide what the right balance is between being effective and being honest."
Stephen Schneider
(leading advocate of the global warming theory)
(in interview for Discover magazine, Oct 1989)
"In the United
States...we have to first convince the American People and the Congress that the climate problem is
real."
former President
Bill Clinton in a 1997 address to the United Nations
Nobody is interested in
solutions if they don't think there's a problem. Given that starting point, I believe it is appropriate to have an
over-representation of factual presentations on how dangerous (global warming) is, as a predicate for opening up the
audience to listen to what the solutions are...
former Vice President Al Gore
(now, chairman and
co-founder of Generation Investment Management--
a London-based business that sells carbon credits)
(in
interview with Grist
Magazine
[IMG]http://www.geocraft.com/W
VFossils/PageMill_Images/pdf_logo.gif[/IMG]May 9, 2006, concerning his book, An Inconvenient Truth)
"In the long run, the
replacement of the precise and disciplined language of science by the misleading language of litigation and advocacy
may be one of the more important sources of damage to society incurred in the current debate over global
warming."
Dr. Richard S.
Lindzen
(leading climate and atmospheric science expert- MIT) (3)
"Researchers pound the
global-warming drum because they know there is politics and, therefore, money behind it. . . I've been critical of
global warming and am persona non
grata."
Dr. William
Gray
(Professor of Atmospheric Sciences at Colorado State University, Fort Collins, Colorado and
leading expert of hurricane prediction )
(in an interview for the Denver Rocky Mountain News, November 28,
1999)
"Scientists
who want to attract attention to themselves, who want to attract great funding to themselves, have to (find a) way
to scare the public . . . and this you can achieve only by making things bigger and more dangerous than they really
are."
Petr Chylek
(Professor of Physics and Atmospheric Science, Dalhousie University, Halifax,
Nova Scotia)
Commenting on reports by other researchers that Greenland's glaciers are melting.
(Halifax
Chronicle-Herald, August 22, 2001) (8)
"Even if the theory of global
warming is wrong, we will be doing the right thing -- in terms of economic policy and environmental
policy."
Tim Wirth , while U.S. Senator, Colorado.
After a short stint as United Nations
Under-Secretary for Global Affairs (4)
he now serves as President, U.N. Foundation, created by
Ted Turner and his $1 billion "gift"
"No matter if the
science is all phony, there are collateral environmental benefits.... Climate change [provides] the greatest chance
to bring about justice and equality in the world."
Christine Stewart, Minister of the
Environment of Canada
recent quote from the Calgary Herald
Unraveling the Earth's Temperature
Record
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G]
photo by: Vin
Morgan
[COLOR
=#0000ff]Palaeo Environment (Ice Cores) Field
WorkBecause accumulating layers of glacial ice
display annual bands which can be dated, similar to annual rings of a tree, the age of ice core samples can be
determined. Continuous ice cores from borings as much as two miles long have been extracted from permanent glaciers
in Greenland, Antarctica, and Siberia. Bubbles of entrapped air in the ice cores can be analyzed to determine not
only carbon dioxide and methane concentrations, but also atmospheric temperatures can be determined from analysis of
entrapped hydrogen and oxygen.
Based on historical air temperatures inferred from ice core analyses from the
Antarctic Vostok station in 1987, relative to the average global temperature in 1900 it has been determined that
from 160,000 years ago until about 18,000 years ago Earth temperatures were on average about 3° C cooler than
today.
Except for two relatively brief interglacial episodes, one peaking about 125,000 years ago (Eemian
Interglacial), and the other beginning about 18,000 years ago (Present Interglacial), the Earth has been under siege
of ice for the last 160,000 years.
As illustrated in this final
graph, over the past 800,000 years the Earth has undergone major swings in warming and cooling at approximately
100,000 year intervals, interrupted by minor warming cycles at shorter intervals. This represents periods of glacial
expansion, separated by distinct but relatively short-lived periods of glacial retreat.
T
emperature data inferred from measurements of the ratio of oxygen isotope ratios in fossil plankton that settled to
the sea floor, and assumes that changes in global temperature approximately tracks changes in the global ice
volume.
Based on data from J. Imbrie, J.D. Hays, D.G. Martinson, A. McIntyre, A.C. Mix, J.J. Morley,
N.G. Pisias, W.L. Prell, and N.J. Shackleton, in A. Berger, J. Imbrie, J. Hats, G. Kukla, and B. Saltzman, eds.,
Milankovitch and Climate, Dordrecht, Reidel, pp. 269-305, 1984.Courtesy of Thomas Crowley,
Remembrance of Things Past:
Greenhouse Lessons from the Geologic
Record
The Polar Ice Cap
Effect
[IMG]http://www.geocraft.com/WVFossils/PageMill_Images/image195.gif[/IM
G]As long as the continent of Antarctica exists at the southern pole of our planet we probably
will be repeatedly
pulled back into
glacial ice ages. This occurs because ice caps, which cannot attain great thickness over open ocean,
can and do achieve great thickness over a polar continent-- like Antarctica. Antarctica used to be located near the
equator, but over geologic time has moved by
continental drift to its
present location at the south pole. Once established, continental polar ice caps act like huge cold sinks, taking
over the climate and growing bigger during periods of reduced solar output. Part of the problem with shaking off the
effects of an ice age is once ice caps are established, they cause solar radiation to be reflected back into space,
which acts to perpetuate global cooling. This increases the size of ice caps which results in reflection of even
more radiation, resulting in more cooling, and so on.
Continental polar ice caps seem to play a particularly
important role in ice ages when the arrangement of continental land masses restrict the free global circulation of
equatorial ocean currents. This is the case with the continents today, as it was during the
Carboniferous Ice
Age when the supercontinent
Pangea stretched from pole to pole 300 million years ago.
Stopping Climate
Change
Putting things in perspective, geologists
tell us our present warm climate is a mere blip in the history of an otherwise cold Earth. Frigid Ice Age
temperatures have been the rule, not the exception, for the last couple of million years. This kind of world is not
totally inhospitable, but not a very fun place to live, unless you are a polar bear.
Some say we are
"nearing the end of our minor interglacial
period" , and may in fact be on the brink of another Ice Age. If this is true, the last thing we
should be doing is limiting carbon dioxide emissions into the atmosphere, just in case they may have a positive
effect in sustaining present temperatures. The smart money, however, is betting that there is some momentum left in
our present warming cycle. Environmental advocates agree: resulting in a shift of tactics from the "
global
cooling" scare of the 1970s to the
"global warming" threat of the 1980s and 1990s.
Now, as we begin the
21st century the terminology is morphing toward
"climate change," whereby no matter the direction of
temperature trends-- up or down-- the headlines can universally blame humans while avoiding the necessity of
switching buzz-words with the periodicity of solar cycles. Such tactics may, however, backfire as peoples' common
sensibilities are at last pushed over the brink.
Global climate cycles of warming and cooling have been a natural
phenomena for hundreds of thousands of years, and it is unlikely that these cycles of dramatic climate change will
stop anytime soon. We currently enjoy a warm Earth. Can we count on a warm Earth forever? The answer is most
likely... no.
Since the climate has always been changing and will likely continue of its own accord to change in
the future, instead of crippling the U.S. economy in order to achieve small reductions in global warming effects due
to manmade additions to atmospheric carbon dioxide, our resources may be better spent making preparations to adapt
to global cooling and global warming, and the inevitable consequences of fluctuating ocean levels, temperatures, and
precipitation that accompany climatic change.
Supporting this view is British scientist
Jane Francis, who
maintains:
" What we are seeing really is just another interglacial phase within our big icehouse
climate." Dismissing political calls for a global effort to reverse climate change, she said, " It's really
farcical because the climate has been changing constantly... What we should do is be more aware of the fact that it
is changing and that we should be ready to adapt to the
change."
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BY:
Monte Hieb
This site last updated October 5,
2007
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References
(1)
A scientific Discussion of Climate
Change, Sallie Baliunas, Ph.D., Harvard- Smithsonian Center for Astrophysics and Willie Soon, Ph.D.,
Harvard- Smithsonian Center for Astrophysics.
(2)
The Effects of Proposals for Greenhouse Gas
Emission Reduction; Testimony of Dr. Patrick J. Michaels, Professor of Environmental Sciences,
University of Virginia, before the Subcommittee on Energy and Environment of the Committee on Science, United States
House of Representatives
(3)
Statement
Concerning Global Warming-- Presented to the Senate Committee on Environmental and Public Works, June
10, 1997, by Dr. Richard S. Lindzen, Massachusetts Institute of Technology
(4) Excerpts
from,"
Our
Global Future: Climate Change", Remarks by Under Secretary for Global affairs, T. Wirth, 15 September
1997. Site maintained by
The Globe - Climate
Change Campaign
(5)
Testimony
of John R. Christy to the Committee on Environmental and Public Works, Department of Atmospheric
Science and Earth System Science Laboratory, University of Alabama in Huntsville, July 10, 1997.
(6) The Carbon
Dioxide Thermometer and the Cause of Global Warming; Nigel Calder,-- Presented at a seminar SPRU (Science and
Technology Policy Research), University of Sussex, Brighton, England, October 6, 1998.
(7) Variation in cosmic ray
flux and global cloud coverage: a missing link in solar-climate relationships; H. Svensmark and E.
Friis-Christiansen, Journal of Atmospheric and Solar- Terrestrial Physics, vol. 59, pp. 1225 - 1232 (1997).
(8)
First International Conference on Global Warming and the Next Ice Age; Dalhousie University, Halifax, Nova
Scotia, sponsored by the Canadian Meteorological and Oceanographic Society and the American Meteorological Society,
August 21-24, 2001.
Additional
Reading
Understanding Common Climate Claims: Dr. Richard S. Lindzen; Draft paper to appear in
the Proceedings of the 2005 Erice Meeting of the World Federation of Scientists on Global
Emergencies.
Geol
ogical Constraints on Global Climate Variability: Dr. Lee C. Gerhard-- A variety of natural climate
drivers constantly change our climate. A slide format presentation. 8.5
MB.
Thoughts of Global Warming: "The
bottom line is that climatic change is a given. It is inescapable, it happens. There is no reason to be very
concerned about it or spend bazillions of dollars to try and even things
out.
NOAA Paleoclimatology: An
educational trip through earths distant and recent past. Also contains useful information and illustrations relating
to the causes of climate change.
Cracking the Ice
Age: From the PBS website-- NOVA online presents a brief tour of the causes of global
warming.
Little Ice
Age (Solar Influence - Temperature): From the online magazine, "CO2
Science."
Solar Variability and Climate
Change: by Willie Soon, January 10,
2000
Earth's Fidgeting
Climate: NASA Science News "It may surprise many people that science cannot deliver an unqualified,
unanimous answer about something as important as climate change"
Bookmarks