Global warming is likely anthropogenic

1. A geological perspective To understand the present, we must understand the past. If warming is not unprecedented, then there is no reason to believe in Anthropogenic warming (AGW). All of the evidence regarding AGW is based on the short-erm 100 year period of warming from 1900 – 2000. Paleoclimatologists say that the 100 year interval is “too short to carry statistical significance regarding long-term climate change. ”1 Geologists have a much longer perspective that greenhouse theorists often don’t account for. Climatologists have a very narrow view of climate within the past 100 years, but cannot fully comprehend the climate. When the past is accounted for, the proof is pretty conclusive: our current warming isn’t that scary, why worry about it? Now, to make this clear: I and geologists are not “deniers”. We accept the planet is warming, and that the climate has changed and will change again. We are skeptical of the man-made global warming conundrum. Here are the reconstructions of the past done by recent papers:1 We can see the modern warm period is cooler than all three warming periods in the past, including the roman and medieval warm periods when humanity flourished. But what if we enter in CO2? Indeed, if CO2 correlates with these temperatures, I am wrong, and I lose. So lets extend the graph to 600 million years. What do we get? Nothing significant.2 Now, my opponent will inevitably have to argue co2 correlates with temperature in the last 100 years, even if it does not in the past, so therefore it must cause the warming today even if it never did in the past. I will refute in detail (if he does that) later. But I will use similar analysis here as I will in a future rebuttal: (1) Correlation does not equal causation. (2) Now, even if CO2 did correlate in the recent interglacial or in history (which it really didn’t), CO2 would have to precede the temperature increase. (3) We need as much data as possible in order to weed out spurious correlations (which is why I am using geological proxies). Now, in the past, is any of this true? No, it is not. There is little correlation between CO2 and temperature (and correlation =/= causation in the current century), and CO2 does not correlate with any temperature nor does it precede temperature. It actually lags temperature. CO2 in the last few hundred thousand years lags the temperature increase by 400 to 1000 years after the warming. When focusing on the modern interglacial, the finding is that “the start of the CO2 increase lagged the start of the temperature increase by 800 years. ”3 Indeed, other analysis’s totally uncouple the two and find “after the termination of the last great ice age, the CO2 content of the air gradually rose by approximately 25 ppm in almost linear fashion between 8,200 and 1,200 years ago, also during a period of time that saw a slow but steady decline in mean global air temperature, which results are obviously just the opposite of what would be expected if changes in atmospheric CO2 drove climate change in the way claimed by the popular CO2-greenhouse effect theory. ”4 Unless my opponent can prove CO2 can be, and has been, a major climate driver and not a secondary forcing agent I see no way he can win this debate. Now, I hope not to confuse the readers or my opponent. CO2 is a greenhouse gas. CO2 can cause some warming, though its potential effects are overstated. Natural factors supersede Carbon Dioxide hands down. There is absolutely no proof outside of climate models that CO2 will cause catastrophic warming, and looking into the past merely demonstrates that point. 2. Plausible natural factors The main driver of climate is the sun. Possibly the engine of our climate. To use an analogy similar to professor Tim Ball, the sun is like the engine of the car, and CO2 is like the screw on the wheel. And then there are two main contributing factors: i) Total solar irradiance (TSI) and ii) the magnetic flux. The TSI is an obvious factor. The hotter the sun, the hotter the planets around it. Without the sun, we would be nothing. There is no need for explanation as to why it could be a cause in modern warming, but if it is. The Magnetic flux is a little more ambiguous. We know it correlates with temperature extremely well, but we don’t have a mechanism. We do not know what is special about this flux. The magnetic flux and solar cycle length correlate like so:5 So, the question is why? Answer: it’s probably cosmic rays! This is the most likely explanation for the magnetic flux vs temperature link. Clouds are a negative feedback. Cosmic rays have been demonstrated to cause more clouds. The fewer cosmic rays, the fewer clouds, and the more warming. Indeed, the scientific literature leads to the conclusion that “weak decreases in cosmic rays … show, as expected, a decreasing effect [of cloud cover]. ”6 During the solar cycle, there is a 3% decrease in clouds (which is why it is warmer when the sun is warmer). Svensmark noted how galactic cosmic rays explain this decrease in cloud cover (note no other theory does) and that cosmic rays can account for nearly all of the warming in the late 20th century.7 As for TSI, the IPCC and others assume in their models that the sun has not warmed significantly since 1950. However, empirical studies my Nicola Scafetta demonstrate “[w]hen taken into account the entire range of possible TSI satellite composite since 1980, the solar contribution to climate change ranges from a slight cooling to a significant warming, which can be as large as 65% of the total observed global warming. ”8 Scafetta notes elsewhere, “the sun contributed as much as… 25–35% of the 1980–2000 global warming. ”9 CONCLUSION Using data from the geologic past it seems hard to accept that CO2 is the main driver of climate change. Instead, solar variations are a more likely cause. 1. . http://eprints.jcu.edu.au... 2. . http://www.geocraft.com... 3. . http://www.co2science.org... 4. Ibid 5. Eigil Friis-Christensen and K. Lassen. “Length of the Solar Cycle: An Indicator of Solar Activity Closely Associated with Climate. ” Science, Volume 254, Number 5032, pp. 698-700, (1991). 6. . http://calderup.wordpress.com...; 7. Svensmark, H. , and Friis-Christensen, E. “Variation of cosmic ray flux and global cloud coverage: A missing link in solar climate relationships. ” Journal of Atmos. Solar-Terr. Phys. 59, 1225– 1232 (1997). 8. Scafetta, N. “Empirical analysis of the solar contribution to global mean air surface temperature change. ” Journal of Atmospheric and Solar-Terrestrial Physics, 71, 1916–1923 (2009). 9. Scafetta, N. , and B. J. West. “Phenomenological solar contribution to the 1900-2000 global surface warming. ” Geophysical Research Letters, (2006).