In the twentieth century, the global average surface temperature rose about 0.6 (+/- 0.2) degrees Celsius. In three distinct trends: First, a strong warming trend of about 0.5 degrees Celsius began in the late nineteenth century and peaked around 1940. Then, oddly, there was a cooling trend from 1940 until the late 1970s. And a modest warming trend occurred from the late 1970s to the present.
But about 80 percent of the carbon dioxide from human activities was added to the air after 1940. Thus increased carbon dioxide in the air cannot account for the pre-1940 warming trend. That trend had to be largely natural. Then, as the air's carbon dioxide content increased most rapidly,(1940-1970)temperatures dropped for nearly 40 years. The maximum increase in warming seen after the 1970s is about 0.1 degree Celsius per decade.
A few Charts.
_This is the alarmist "hockey stick" chart:
http://news.bbc.co.uk/1/shared/spl/hi/pop_ups/04/sci_nat_enl_1092666337/html/1.stm
_From Climatic Research Unit(UK):
http://www.cru.uea.ac.uk/cru/climon/data/themi/g17.htm
_The Huang temperature chart:
http://www.unc.edu/~sstaff/images/huangcurve.jpg
_This chart compares solar activity(red),CO2(blue), and temperature(black):
http://www.unc.edu/%7Esstaff/images/craytemp.jpg
Computer Climate Models presently in use cannot even simulate known climate variations(i.e. the warming that occurred from approximately 1910 to 1940),why should anyone believe these models can predict future climate variations.
Incroyant.
Originally posted by c99uxhmmm, only ppm, can't be important. a standard military 5.56mm bullet (4g) is only 50 ppm in comparision to the weight of a 80 kg person. so i guess that has no effect on the person either...
Isn't it amazing, that all these scientists are now running round screaming "Global Warming", "C02" and stuff like that?
Yesterday on the news I saw the latest report which said that amount of C02 in the atmosphere had increased from 368ppm (0.0368% of all the gas in the atmosphere...) to 380.7ppm (0.03807%...) in the past 25 years. It was only 349ppm (0.0 ...[text shortened]... hat caused the desert to expand and the sea to rise all those thousands of years ago?
Originally posted by xshttp://www.grida.no/climate/ipcc_tar/wg1/fig2-1.htm
In the twentieth century, the global average surface temperature rose about 0.6 (+/- 0.2) degrees Celsius. In three distinct trends: First, a strong warming trend of about 0.5 degrees Celsius began in the late nineteenth century and peaked around 1940. Then, oddly, there was a cooling trend from 1940 until the late 1970s. And a modest warming trend occurred from ),why should anyone believe these models can predict future climate variations.
Incroyant.
What was that again?
Your first two graphs show the same thing, only on different time scales.
Your second two show the long term situation, in thousands, and millions of years. Neither of these things account for the sharp up-turn in global temp. ~1C in the last 100 years.