There's no question that the world is experiencing a slight increase in temperature. However, there is considerable question as to the validity of the conclusion its the result of increases in atmospheric polution.
All available evidence points to the existence of a warm period between 800 and 1100 years ago, with temperatures as high as 4 degrees C higher than we're experiencing now...followed and preceded by lower temperature periods. We've some records of this warming trend from documents surviving from this time period...but the best support I've seen came from combinations of data (tree rings around the globe, coral stria, etc).
Check the research by Kuo-Yen Wei, University of Taiwan. Here's an overview I googled: http://64.233.167.104/search?q=cache:LjjuDRoWgOAJ:corelab.iag.ntou.edu.tw/2006/Publication%2520(1996-2001)/Wei/%E9%AD%8F%E5%9C%8B%E5%BD%A5MD972143-WPES.pdf+Documenting+Past+Environmental+Changes+in+Taiwan+and+Adjacent+Areas&hl=en&ct=clnk&cd=1&gl=us. The summary:
"The interlaminated dark and light colored lake sediments obtained from several mountain lakes appear to reflect large-scale wet and dry cycles over the past 2400 years (Chen et al., 1993; Lou et al, in press). The detected 450-years periodicity is similar to that of the solar oscillation. The Medieval Warm Period (1000-1300 AD) and the Little Ice Age (1300-1850 AD) were recognized (Lou et al., in press). These two epochs were also identified from palynological records from the Central Range (Liew et al., 1995)"
They also referred to studies of annual to seasonal records from tree-rings.
"Studies of tree rings of Taiwan fir allowed to reconstruct past summer and winter temperatures of the alpine mountain area during the past 300 years. It is demonstrated that cold climate prevailed during the Little Ice Age (Tsou and Liu, 1995)."
Finally in a synopsis of the various proxies studied in and around Taiwan:
"During the past 2000 years, the climate has become warmer and wetter, intervened with the conspicuous Medieval Warm Period (1000-1300 AD) and the Little Ice Age (1300-1850 AD). Tree-ring data confirmed also the effect of the Little Ice Age in alpine Taiwan mountains. Fluctuation of humidity over the past 2,400 years as derived from lake sediments suggests that the recognized dry/cold periods coincide with major historical commotion events in Chinese history."
From a variety of proxy indicators, the same events are found even here, on the western rim of the Pacific Ocean.
The Taiwan researchers even linked major "commotion events" in mainland China with these climatic events. According to Hong et al. (Hong Y. et al., "Response of Climate to Solar Forcing Recorded in a 6000-year delta18O Time-Series of Chinese Peat Cellulose", The Holocene, 2000) these events were also climate driven. Their study of oxygen isotopes in a peat bog in north-eastern China close to the border with North Korea, revealed a 6,000 year temperature history which was compared with carbon 14 solar proxies to match the temperature history with solar change.
They estimated the temperature between 1100 and 1200 AD at around 2°F warmer than today, matching the Medieval Warm Period, confirmed by the existence at that time of plant remains from species that normally exist only in southern China. They found very cold temperatures between around 1550 and 1750, matching the Little Ice Age found elsewhere.
Finally, they also found the solar connection in these climate changes, the carbon 14 solar proxy correlating with the oxygen 18 temperature proxy. In other words, the sun caused climate changes in China.
Also check Winter and company's research in the Carribean: http://adsabs.harvard.edu/abs/2000GeoRL..27.3365W. The summary:
Measurements of oxygen isotopes in coral skeletons from Puerto Rico by Winter ("Caribbean Sea Surface Temperatures: Two-to-Three Degrees Cooler than Present During the Little Ice Age", Geophysical Research Letters, Oct 15 2000), compared modern isotope ratios with those of the distant past. Calibration of the coral isotopes to provide a sea surface temperature proxy was based on modern sea surface temperature records around Puerto Rico for the period 1983-1989. This provided the baseline for the researchers to test the coral for temperatures during known cold phases of the Little Ice Age, 1700-1710, 1780-1785, and 1810-1815. They found that during the Little Ice Age, sea surface temperature in the Caribbean was 2 - 3°C cooler than it is today, a truly massive reduction in temperature which could by no stretch of the imagination be local.
And finally Keigwin and company's work in the Sargasso: http://www.sciencemag.org/cgi/content/short/274/5292/1503, and http://www.whoi.edu/institutes/occi/viewArticle.do?id=3842. And the summary:
In the Sargasso Sea (an area popularly known as the `Bermuda Triangle'), radiocarbon dating of marine organisms in sea bed sediments by L. Keigwin ("The Little Ice Age and Medieval Warm Period in the Sargasso Sea", Science, 1996)demonstrates that sea surface temperatures were around 2°F cooler than today around 400 years ago (the Little Ice Age), and around 2°F warmer than today 1,000 years ago (the Medieval Warm Period). In addition, the data also demonstrates that the period before 500 BC (referred to as the Holocene Climatic Optimum) saw temperatures up to 4°F warmer, and without any greenhouse gas component to cause it.
And my take.....warming is real, without doubt, but its minor and in no way to a degree that indicates a man made influence (0.6 C in the last century, and 2/3 of that increase before FDR took office). Yes, glacial ice is melting, but it refreezes elsewhere, and it always does this. Cap melt is nothing new.
However, oil is a limited resource, and will expire in the blink of an eye (within the next century by some estimates). Coal is much the same. In addition breathing brown air....well, sucks.
We need to stop wasting billions on warming research, which is what many of these "scientists" seem to want us to continue funding. If they are right, we know the cause: burning fossil fuel. Whether this is right or wrong, funding alternative fuels MUST be our primary thrust. We need to stop spending more on global warming research than we spend on alternative fuel research. Fund hyrdogen. Fund geothermal power. This will resolve any potential problem with man made pollutants causing warming, and will definitely get us off consuming petroleum.
Thanks for the time.
