Climate Change In Perspective: An Honest View Of History

I think the following article and graphs illustrate very clearly the absurdity of attributing any recent global warming or climate change to man-caused carbon dioxide emissions. Assuming the studies of ice cores shown is accurate, and I've seen little dispute on the subject, it is obvious the climate has been changing continuously for the past million years at greater rates and absolute values than we have seen since the beginning of the industrial revolution.

Read the article; it is simple, obvious, and backed by factual, scientific measurement and observation. There is no hype, no manipulating data, no politics, and the information is available to anyone and everyone. It is clear the myth of man-caused global warming is a fraud. The public has been thoroughly deceived. ClimateGate proves that.

Thanks to http://antigreen.blogspot.com/ for the article. Visit that blog, it is excellent.
Peter

Some perspective

I’m looking at the temperature record as read from this central Greenland ice core. It gives us about as close as we can come to a direct, experimental measurement of temperature at that one spot for the past 50,000 years. As far as I know, the data are not adjusted according to any fancy computer climate model or anything else like that. So what does it tell us about, say, the past 500 years? (the youngest datum is age=0.0951409 (thousand years before present) — perhaps younger snow doesn’t work so well?):



Well, whaddaya know — a hockey stick. In fact, the “blade” continues up in the 20th century at least another half a degree. But how long is the handle? How unprecedented is the current warming trend?



Yes, Virginia, there was a Medieval Warm Period, in central Greenland at any rate. But we knew that — that’s when the Vikings were naming it Greenland, after all. And the following Little Ice Age is what killed them off, and caused widespread crop failures (and the consequent burning of witches) across Europe. But was the MWP itself unusual?



Well, no — over the period of recorded history, the average temperature was about equal to the height of the MWP. Rises not only as high, but as rapid, as the current hockey stick blade have been the rule, not the exception.



In fact for the entire Holocene — the period over which, by some odd coincidence, humanity developed agriculture and civilization — the temperature has been higher than now, and the trend over the past 4000 years is a marked decline. From this perspective, it’s the LIA that was unusual, and the current warming trend simply represents a return to the mean. If it lasts.



From the perspective of the Holocene as a whole, our current hockeystick is beginning to look pretty dinky. By far the possibility I would worry about, if I were the worrying sort, would be the return to an ice age — since interglacials, over the past half million years or so, have tended to last only 10,000 years or so. And Ice ages are not conducive to agriculture.



… and ice ages have a better claim on being the natural state of Earth’s climate than interglacials. This next graph, for the longest period, we have to go to an Antarctic core (Vostok):



In other words, we’re pretty lucky to be here during this rare, warm period in climate history. But the broader lesson is, climate doesn’t stand still. It doesn’t even stand stay on the relatively constrained range of the last 10,000 years for more than about 10,000 years at a time.

SOURCE

What Causes Ice Ages To Begin And End?

Here is an excellent summary of the causes of the beginnings and endings of ice ages. Since Ice Ages and their associated warming periods, or interglacials, are the most extreme climate changes the Earth goes through, it is important to note that there is NO mention of atmospheric carbon dioxide playing a role.

It seems the amount of carbon dioxide in the atmosphere responds to changes in temperature. When the oceans warm, they release CO2 and it increases in the atmosphere. When the oceans cool, they absorb more CO2. Mankind's miniscule contribution of CO2 from the burning of fossil fuels seems to literally have no affect at all on climate change. The author of this short essay is a very accomplished glacial scientist and ecologist and author. I wonder why he isn't speaking out about the myth of man-caused global warming?
Peter

source:

What causes ice-ages?
Fluctuations in the amount of insolation (incoming solar radiation) are the most likely cause of large-scale changes in Earth's climate during the Quaternary. In other words, variations in the intensity and timing of heat from the sun are the most likely cause of the glacial/interglacial cycles. This solar variable was neatly described by the Serbian scientist, Milutin Milankovitch, in 1938. There are three major components of the Earth's orbit about the sun that contribute to changes in our climate. First, the Earth's spin on its axis is wobbly, much like a spinning top that starts to wobble after it slows down. This wobble amounts to a variation of up to 23.5 degrees to either side of the axis. The amount of tilt in the Earth's rotation affects the amount of sunlight striking the different parts of the globe. The greater the tilt, the stronger the difference in seasons (i.e., more tilt equals sharper differences between summer and winter temperatures). The range of motion in the tilt (from left-of-center to right-of-center and back again) takes place over a period of 41,000 years. As a result of a wobble in the Earth's spin, the position of the Earth on its elliptical path changes, relative to the time of year. This phenomenon is called the precession of equinoxes. The cycle of equinox precession takes 23,000 years to complete. In the growth of continental ice sheets, summer temperatures are probably more important than winter.

How does the ice build up?
Throughout the Quaternary period, high latitude winters have been cold enough to allow snow to accumulate. It is when the summers are cold, (i.e., summers that occur when the sun is at its farthest point in Earth's orbit), that the snows of previous winters do not melt completely. When this process continues for centuries, ice sheets begin to form. Finally, the shape of Earth's orbit also changes. At one extreme, the orbit is more circular, so that each season receives about the same amount of insolation. At the other extreme, the orbital ellipse is stretched longer, exaggerating the differences between seasons. The eccentricity of Earth's orbit also proceeds through a long cycle, which takes 100,000 years. Major glacial events in the Quaternary have coincided when the phases of axial tilt, precession of equinoxes and eccentricity of orbit are all lined up to give the northern hemisphere the least amount of summer insolation.
What makes the ice melt when the glaciation is over?

Major interglacial periods have occurred when the three factors line up to give the northern hemisphere the greatest amount of summer insolation. The last major convergence of factors giving us maximum summer warmth occurred 11,000 years ago, at the transition between the last glaciation and the current interglacial, the Holocene. During the late Pleistocene, the Rocky Mountain regions of Canada and the regions farther west were almost engulfed in the Cordilleran Ice Sheet, while most of Canada east of the Rockies and the north-central and northeastern United States were covered by the Laurentide Ice Sheet. The divide between the two ice sheets lay east of the Rockies, with the two ice bodies meeting near the U.S.-Canadian border in eastern Montana. The Laurentide ice sheet is thought to have been as much as two miles thick at the center.
Click here to return to Scott Elias' home page

Scott A. Elias is a fellow of the Institute of Arctic and Alpine Research, University of Colorado, and a research associate of the University of Alaska Museum. He is the author of Ice-Age History of Alaskan National Parks (1995) and Quaternary Insects and their Environments (1994), published by Smithsonian Institution Press.

CO2 Did Not End The Last Ice Age, New Study Says

Here is a summary of a new study concluding that rising atmospheric carbon dioxide levels did not cause the ending of the last ice age. It further states the probable cause was an increase in solar energy. They do say CO2 may have "accelerated" the warming. So then the question is how MUCH does CO2 accelerate warming caused by the Sun?
Peter

from: http://www.sciencedaily.com/releases/2007/09/070927154905.htm

Carbon Dioxide Did Not End The Last Ice Age, Study Says
ScienceDaily (Oct. 2, 2007) — Carbon dioxide did not cause the end of the last ice age, a new study in Science suggests, contrary to past inferences from ice core records.
"There has been this continual reference to the correspondence between CO2 and climate change as reflected in ice core records as justification for the role of CO2 in climate change," said USC geologist Lowell Stott, lead author of the study, slated for advance online publication Sept. 27 in Science Express.
"You can no longer argue that CO2 alone caused the end of the ice ages."

Deep-sea temperatures warmed about 1,300 years before the tropical surface ocean and well before the rise in atmospheric CO2, the study found. The finding suggests the rise in greenhouse gas was likely a result of warming and may have accelerated the meltdown -- but was not its main cause.
The study does not question the fact that CO2 plays a key role in climate.
"I don't want anyone to leave thinking that this is evidence that CO2 doesn't affect climate," Stott cautioned. "It does, but the important point is that CO2 is not the beginning and end of climate change."

While an increase in atmospheric CO2 and the end of the ice ages occurred at roughly the same time, scientists have debated whether CO2 caused the warming or was released later by an already warming sea.
The best estimate from other studies of when CO2 began to rise is no earlier than 18,000 years ago. Yet this study shows that the deep sea, which reflects oceanic temperature trends, started warming about 19,000 years ago.
"What this means is that a lot of energy went into the ocean long before the rise in atmospheric CO2," Stott said.

But where did this energy come from" Evidence pointed southward.
Water's salinity and temperature are properties that can be used to trace its origin -- and the warming deep water appeared to come from the Antarctic Ocean, the scientists wrote.
This water then was transported northward over 1,000 years via well-known deep-sea currents, a conclusion supported by carbon-dating evidence.
In addition, the researchers noted that deep-sea temperature increases coincided with the retreat of Antarctic sea ice, both occurring 19,000 years ago, before the northern hemisphere's ice retreat began.

Finally, Stott and colleagues found a correlation between melting Antarctic sea ice and increased springtime solar radiation over Antarctica, suggesting this might be the energy source.
As the sun pumped in heat, the warming accelerated because of sea-ice albedo feedbacks, in which retreating ice exposes ocean water that reflects less light and absorbs more heat, much like a dark T-shirt on a hot day.
In addition, the authors' model showed how changed ocean conditions may have been responsible for the release of CO2 from the ocean into the atmosphere, also accelerating the warming.

The link between the sun and ice age cycles is not new. The theory of Milankovitch cycles states that periodic changes in Earth's orbit cause increased summertime sun radiation in the northern hemisphere, which controls ice size.
However, this study suggests that the pace-keeper of ice sheet growth and retreat lies in the southern hemisphere's spring rather than the northern hemisphere's summer.
The conclusions also underscore the importance of regional climate dynamics, Stott said. "Here is an example of how a regional climate response translated into a global climate change," he explained.

Stott and colleagues arrived at their results by studying a unique sediment core from the western Pacific composed of fossilized surface-dwelling (planktonic) and bottom-dwelling (benthic) organisms.
These organisms -- foraminifera -- incorporate different isotopes of oxygen from ocean water into their calcite shells, depending on the temperature. By measuring the change in these isotopes in shells of different ages, it is possible to reconstruct how the deep and surface ocean temperatures changed through time.

If CO2 caused the warming, one would expect surface temperatures to increase before deep-sea temperatures, since the heat slowly would spread from top to bottom. Instead, carbon-dating showed that the water used by the bottom-dwelling organisms began warming about 1,300 years before the water used by surface-dwelling ones, suggesting that the warming spread bottom-up instead.

"The climate dynamic is much more complex than simply saying that CO2 rises and the temperature warms," Stott said. The complexities "have to be understood in order to appreciate how the climate system has changed in the past and how it will change in the future."

Stott's collaborators were Axel Timmermann of the University of Hawaii and Robert Thunell of the University of South Carolina. Stott was supported by the National Science Foundation and Timmerman by the International Pacific Research Center.

Stott is an expert in paleoclimatology and was a reviewer for the Intergovernmental Panel on Climate Change. He also recently co-authored a paper in Geophysical Research Letters tracing a 900-year history of monsoon variability in India.
The study, which analyzed isotopes in cave stalagmites, found correlations between recorded famines and monsoon failures, and found that some past monsoon failures appear to have lasted much longer than those that occurred during recorded history. The ongoing research is aimed at shedding light on the monsoon's poorly understood but vital role in Earth's climate.

Adapted from materials provided by University of Southern California.

A Quick Summary of Ice Ages and Warming

This is an excellent summary of the most recent ice age and subsequent warming period, leading up to where we are today. It graphically helps put things in perspective.
Peter

from: http://mysite.verizon.net/mhieb/WVFossils/ice_ages.html

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.

( view full size map)
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 glaciers or extreme desert. Forests were rare.
Not a very fun place to live.

(view full size map)

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

Periods 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)

Global 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?

Human Evolution and Climate Change: We Will Survive

There is a lot of fear being spread around the world about global warming and catastrophic climate change. Some fools are even promoting a series of music events on all seven continents to promote their message that we must act now. They say the crises is upon us and the need is urgent to stop global warming.

Unfortunately these people always seem to ignore science, history, and even simple common sense. They rely on their feelings rather than reason and logical thought. Read this article about human evolution. Modern humans evolved, spread and thrived through ice ages, and every kind of natural disaster and climate changes, more severe than we are experiencing now. This is not mere speculation, but fact based on the study of written history and archaeology, (ancient Egyptians, Mayans, Aztecs, etc.). That is not all.

Now, as the following article explains, DNA evidence in human genes is showing how remarkably adaptable human beings are to changes in climate, diet, exposure to diseases, and probably everything else in our environment. Are we being unnecessarily frightened by current weather events and global warming? Only you can answer that question for yourself. Maybe it is just human nature to be afraid, to be cautious. Maybe that helps our survival. My advice is to not believe everything you are told or hear.
Peter

from: http://www.nytimes.com/2007/06/26/science/26human.html?pagewanted=1&th&emc=th

Humans Have Spread Globally, and Evolved Locally

By NICHOLAS WADE
Published: June 26, 2007

Historians often assume that they need pay no attention to human evolution because the process ground to a halt in the distant past. That assumption is looking less and less secure in light of new findings based on decoding human DNA.

People have continued to evolve since leaving the ancestral homeland in northeastern Africa some 50,000 years ago, both through the random process known as genetic drift and through natural selection. The genome bears many fingerprints in places where natural selection has recently remolded the human clay, researchers have found, as people in the various continents adapted to new diseases, climates, diets and, perhaps, behavioral demands.

A striking feature of many of these changes is that they are local. The genes under selective pressure found in one continent-based population or race are mostly different from those that occur in the others. These genes so far make up a small fraction of all human genes.

A notable instance of recent natural selection is the emergence of lactose tolerance — the ability to digest lactose in adulthood — among the cattle-herding people of northern Europe some 5,000 years ago. Lactase, the enzyme that digests the principal sugar of milk, is usually switched off after weaning. But because of the great nutritional benefit for cattle herders of being able to digest lactose in adulthood, a genetic change that keeps the lactase gene switched on spread through the population.

Lactose tolerance is not confined to Europeans. Last year, Sarah Tishkoff of the University of Maryland and colleagues tested 43 ethnic groups in East Africa and found three separate mutations, all different from the European one, that keep the lactase gene switched on in adulthood. One of the mutations, found in peoples of Kenya and Tanzania, may have arisen as recently as 3,000 years ago.

That lactose tolerance has evolved independently four times is an instance of convergent evolution. Natural selection has used the different mutations available in European and East African populations to make each develop lactose tolerance. In Africa, those who carried the mutation were able to leave 10 times more progeny, creating a strong selective advantage.

Researchers studying other single genes have found evidence for recent evolutionary change in the genes that mediate conditions like skin color, resistance to malaria and salt retention.
The most striking instances of recent human evolution have emerged from a new kind of study, one in which the genome is scanned for evidence of selective pressures by looking at a few hundred thousand specific sites where variation is common.

Last year Benjamin Voight, Jonathan Pritchard and colleagues at the University of Chicago searched for genes under natural selection in Africans, Europeans and East Asians. In each race, some 200 genes showed signals of selection, but without much overlap, suggesting that the populations on each continent were adapting to local challenges.

Another study, by Scott Williamson of Cornell University and colleagues, published in PLoS Genetics this month, found 100 genes under selection in Chinese, African-Americans and European-Americans.
In most cases, the source of selective pressure is unknown. But many genes associated with resistance to disease emerge from the scans, confirming that disease is a powerful selective force. Another category of genes under selective pressure covers those involved in metabolism, suggesting that people were responding to changes in diet, perhaps associated with the switch from hunting and gathering to agriculture.
(the article is continued at the original source)