Silent_One said:
Natoma wrote:
These reports have stated unequivocably that temperature changes are measured in the sheeting of the ice, rings in very old trees, as well as geologic layers in the earth. And the overall temperature shifts studied from these sources shows that human interference is indeed changing the environment more rapidly than nature has ever done.
Well here's a different opinion on geologic temp. changes-
http://www.envirotruth.org/myth_1.cfm
Dr. Tim Patterson, professor of earth sciences at Ottawa's Carleton University, says this is very unlikely. The geologic record reveals that the only constant about climate is change.
Long before our species inhabited the Earth, there were far more extreme changes in climate than what we see now. In the past million years, the Earth has been subjected to at least 33 ice ages and interglacial warm periods where temperatures soared far above that ever recorded in humanity's short history.
Patterson and others show that, even in the past thousand years, there were periods much warmer and colder than today.
Click
http://www.john-daly.com/nasa.gif to see how temperature has varied since 1979.
Click
http://www.saf.ab.ca/pdf/figure_1.pdf to see how temperature has varied in the past millennia.
Click
http://www.saf.ab.ca/pdf/figure_2.pdf to see how it has varied in the past 18,000 years.
Click
http://www.saf.ab.ca/pdf/figure_3.pdf to see how it has varied in the past 160,000 years.
For more than 90 percent of Earth's history, conditions were much warmer than today. Two million years ago forests extended nearly to the North Pole. As recently as 125,000 years ago, temperatures were high enough that hippopotami and other animals now found only in Africa made their homes in northern Europe.
However, over the last 1.6 million years, it has generally been much cooler than this, with periodic rapid fluctuations from cooler to warmer intervals known as interglaciations. The causes of these dramatic climate variations include continental drift, changes in ocean/atmospheric circulation, natural wobbles in the Earth's orbit called Milankovitch cycles and variations in solar energy.
Despite a 0.7 degree C warming that has occurred over the past century (as much warming occurred before 1940 as since then, even though the large majority of the CO2 buildup in the atmosphere occurred after 1940) , overall, global temperatures have dropped about 2°C over the past 5,000 years (depending on latitude: a 6 degree C drop in some Arctic areas; a 0.5 degree C drop in some lower latitudes). Another ice age is expected to begin within the next few thousand years and so any gradual global warming could be a blessing, as it could delay the onset of the next glacial period, or at least reduce its severity.â€
After reading the PDFs, I compared the temperature differentials within each century to the temperature shift from 1900 - 2000, as well as the projected temperature shift from 2000 - 2100.
The pdf here,
http://www.saf.ab.ca/pdf/figure_1.pdf, shows a very detailed degree of temperature variation. Thanks yet again Silent_One for the research. Much appreciated.
1000 - 1100: 0.2+
1100 - 1200: 0.1+
1200 - 1300: 0.1-
1300 - 1400: 0.6-
1400 - 1500: 0.0 (shifted up 0.2, then down 0.2 during the century)
1500 - 1600: 0.2-
1600 - 1700: 0.0 (shifted up 0.2, then down 0.2 during the century)
1700 - 1800: 0.0 (shifted up 0.3, then down 0.3 during the century)
1800 - 1900: 0.6+
1900 - 2000: 0.7+
2000 - 2100: 1.0 - 3.0+ (projected)
In this PDF,
http://www.saf.ab.ca/pdf/figure_2.pdf, the temperature variations follow roughly the same pattern as well. The massive increases or drops in temperature occurred over the course of 500 to 2000 years. We're talking about a change of 1-4 (+/-) degrees Celcius, which is enough for instance, to turn a polar ice cap into an ocean, or turn a desert into a forest, or vice versa.
What should be noted is that none of the changes displayed in either PDF showed sustained changes of 2-5 degrees Celcius changes (+/-) occurring in the span of 300 years, especially with a 1-3 degree sustained shift in temperature over the course of one century.
That is the main point of contention today among scientists. No one disputes the record of temperature fluctuation derived from ice cores, tree rings, fossil records, etc. What is in dispute today is the rapidity of temperature fluctuation over the past 200 years. Considering the advent of massively polluting technologies in the past 200 years, courtesy of the industrial revolution, we now have a shift in the balance of the normal planetary warming and cooling cycles. They have become, thus far, more pronounced and faster.
One thing that these PDFs do not convey, however, is the Carbon Load the oceans and forests can sustain. Think of the oceans as one big heatsink and carbon loading machine. The forests also perform the same function. Oceans can absorb 3.8 Billion tons of carbon every year, and disperse it naturally.
It should be noted that the United States alone is responsible for roughly 20 Carbon Tons released into the atmosphere, per person, every year. That works out to roughly 5 Billion Tons of Carbon (pop. est. at 250 Million). The rest of the world emits roughly the same amount, which leads to a rough estimate of 8 - 12 Billion Tons of Carbon released into the environment, worldwide, every year.
Let's stick with the conservative estimate of 8 Billion Tons of Carbon. Since the oceans can absorb roughly 3.8 Billion tons of carbon, and in the last recorded year of carbon emissions we went over the global carbon load amount by 1.4 Billion tons, it's safe to assume that the forests can absorb about 2.8 Billion tons, given a starting point of 8 Billion Carbon Tons released into the environment. This makes sense since there is far less forest than ocean. The excess carbon load was measured by how much carbon was introduced into the atmosphere that did not get absorbed anywhere. There was a 1.4 Billion ton excess.
This is one of the reasons why scientists are expecting the huge jump in worldwide temperature in the next century, because we only in the past 5-10 years hit the carbon load limit of the planet, and exceeded it. It's not coincidence that the period from 1930 - 1980 was the hottest recorded 50 year period on record in the past 1,000 years, when using carbon dating methods on ice, trees, and fossils, and that the decade from 1990 - 2000 had 3 of the hottest years on record ever (1993, 1994, and 1998). 1991 - 1992 were cooled because of the eruption of Mount Pinatubo in the Phillippines, which caused worldwide temperatures to drop during that two year period by 0.2 degrees, before heating up rapidly in 1993 as the cloud cover dispersed.
With the oceans and the diminishing forest cover only able to absorb roughly 7 Billion Carbon Tons annually, we're obviously at a point where we're dumping carbon into the atmosphere, and it will linger. It has also been proven that enough carbon dioxide in the atmosphere can and will produce a greenhouse effect. With the natural absorption of the earth nullified by our current rates of carbon dumping, it's only a matter of time before we see the results of these actions.
According to projections, we'll see that shift in this century. Btw, sea levels have risen 4" since 1900 due to glacial melts at the poles. That melting is expected to accelerate tremendously in the 21st century due to the accompanying rise in temperature.
