first of all "global warming" started BEFORE the industrial revolution.
Second of all, yes, there is an effect due to increased carbon emmissions that may cause us to go warmer for a longer period of time, but that dont mean another ice age isnt going to come......our current warming trend has spanned about 18,000 years, normal warming trends typically last 15,000 to 20,000 years with 80,000 years of freeze.......next ice age is due to hit at any time. The only thing carbon output will do is either increase the temp during the current warming trend, or delay the onset of the next cooldown. It cant prevent it though. Had u looked at the research instead of regurgitating enviromentalist propoganda to gain funding for their research, you would know this.
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.
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.
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?
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
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(1) Astronomical Causes
11 year and 206 year cycles: Cycles of solar variability ( sunspot activity )
21,000 year cycle: Earth's combined tilt and elliptical orbit around the Sun ( precession of the equinoxes )
41,000 year cycle: Cycle of the +/- 1.5° wobble in Earth's orbit ( tilt )
100,000 year cycle: Variations in the shape of Earth's elliptical orbit ( cycle of eccentricity )
(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.
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:
1. 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.
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.
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 on the increase for 18,000 years. Interestingly, CO2 lags an average of about 800 years behind the temperature changes-- confirming that CO2 is not a primary driver of the temperature changes .
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.
3. Total human contributions to greenhouse gases account for only about 0.28% of the "greenhouse effect" . 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.
4. If global warming is caused by CO2 in the atmosphere then does CO2 also cause increased sun activity too?
variations in sun activity are generally proportional to both variations in atmospheric CO2 and atmospheric temperature .
Put another way, rising Earth temperatures and increasing CO2 may be "effects" and our own sun the "cause".
The Polar Ice Cap Effect
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."
Source:
http://www.geocraft.com/WVFossils/ice_ages.html
