Mankind Is the Main Cause of Global Warming

For R3, I will focus on rebutting Con's R2. "The Great Global Warming Swindle" Much of my opponent's arguments basically borrows from ideas that haven't held up in a long while and are generally dismissed by the vast majority of climate change scientists. This article (6) in New Scientist articulately explains: "Take the repeated claims that recent global warming is mostly or all due to solar changes. In 1991, for instance, a paper in Science (7) claimed there was a striking correlation between variations in the solar cycle length and temperature between 1880 and 1980, suggesting greenhouse gases have not played as big a role as thought. However, the correlation has not held up after 1980 (8). What is more, it turns out that the apparent correlation before 1980 is due to manipulation of the data (9). Despite being discredited, this graph is still being presented as evidence against human-induced global warming today (see The Great Global Warming Swindle entry in Wikipedia). Similarly, studies suggesting that the lower atmosphere and the oceans are cooling, contrary to what climate models predict, have turned out to be wrong. Later studies have shown the apparent coolings to be a result of errors in equipment or calibration (See Sceptics forced into climate climb-down) (9). By contrast, the famous "hockey stick" graph has been the subject of a determined campaign to discredit it (see The hockey stick graph has been proven to be wrong) (10). Yet later temperature reconstructions and other evidence back the key conclusions of the original hockey stick study (See Climate: The great hockey stick debate.)" Just How Much Influence DOES Solar Energy Have? The big sticking point in our debate has been the issue of precisely how much influence the sun has on global warming. For this, we must look to what has been found by actual science (11): "As supplier of almost all the energy in Earth"s climate, the sun has a strong influence on climate. A comparison of sun and climate over the past 1150 years found temperatures closely match solar activity (Usoskin 2005). However, after 1975, temperatures rose while solar activity showed little to no long-term trend. This led the study to conclude, ""during these last 30 years the solar total irradiance, solar UV irradiance and cosmic ray flux has not shown any significant secular trend, so that at least this most recent warming episode must have another source." In fact, a number of independent measurements of solar activity indicate the sun has shown a slight cooling trend since 1960, over the same period that global temperatures have been warming. Over the last 35 years of global warming, sun and climate have been moving in opposite directions. An analysis of solar trends concluded that the sun has actually contributed a slight cooling influence in recent decades (Lockwood 2008)." This conclusion is confirmed by many studies finding that while the sun contributed to warming in the early 20th Century, it has had little contribution (most likely negative) in the last few decades. For the purposes of space, these are just a few of the peer reviewed papers I can reference. I have more on demand: Huber and Knutti (2011): "Even for a reconstruction with high variability in total irradiance, solar forcing contributed only about 0.07"C (0.03-0.13"C) to the warming since 1950." Erlykin 2009: "We deduce that the maximum recent increase in the mean surface temperature of the Earth which can be ascribed to solar activity is 14% of the observed global warming." Benestad 2009: "Our analysis shows that the most likely contribution from solar forcing a global warming is 7 " 1% for the 20th century and is negligible for warming since 1980." Lockwood 2008: "It is shown that the contribution of solar variability to the temperature trend since 1987 is small and downward; the best estimate is -1.3% and the 2? confidence level sets the uncertainty range of -0.7 to -1.9%." Mars Con appeals to the work of Khabibullo Abdusamatov (12): "Abdussamatov claims that "global warming results not from the emission of greenhouse gases into the atmosphere, but from an unusually high level of solar radiation and a lengthy"almost throughout the last century"growth in its intensity."[4] This view contradicts the mainstream scientific opinion on climate change as well as accepted reconstructions of solar activity.[5][6][7] He has asserted that "parallel global warmings"observed simultaneously on Mars and on Earth"can only be a straightline consequence of the effect of the one same factor: a long-time change in solar irradiance."[8] This assertion has not been accepted by the broader scientific community, some of whom have stated that "the idea just isn"t supported by the theory or by the observations" and that it "doesn"t make physical sense."[9][10]" The above article puts it mildly about him being not widely accepted. He has zero papers published in peer review journals, he is a mathematician and astrophysicist " not climatologist " and is a well known cuckoo on CC denier lists. He is not even part of the mere 24 articles out of 13,950 peer reviewed articles on climate change between 1991-2012 that reject global warming (13), not that it would help his case much for as it is so delightfully put: "Of one thing we can be certain: had any of these [24 peer reviewed] articles presented the magic bullet that falsifies human-caused global warming, that article would be on its way to becoming one of the most-cited in the history of science." But to tackle the actual Mars claim, let's again look at what the experts are saying (14): "The Sun"s energy output has not increased since direct measurements began in 1978 (see Climate myth special: Global warming is down to the Sun, not humans). If increased solar output really was responsible, we should be seeing warming on all the planets and their moons, not just Mars and Pluto. One theory is that winds have recently swept some areas of Mars clean of dust, darkening the surface, warming the Red Planet and leading to further increases in windiness " a positive feedback effect (see Dust blamed for warming on MarsMovie Camera). There is a great deal of uncertainty, though. The warming could be a regional effect. And recent results from the thermal imaging system on the Mars Odyssey probe suggest that the polar cap is not shrinking at all, but varies greatly from one Martian year to the next, although the details have yet to be published." And also (15): "Recently, there have been some suggestions that "global warming" has been observed on Mars (e.g. here). These are based on observations of regional change around the South Polar Cap, but seem to have been extended into a "global" change, and used by some to infer an external common mechanism for global warming on Earth and Mars (e.g. here and here). But this is incorrect reasoning and based on faulty understanding of the data." Thus, the Mars claims must also be considered thoroughly discounted. Con may now begin R4. Sources (6) http://www.newscientist.com... (7) http://dx.doi.org... (8) http://www.newscientist.com... (9) http://environment.newscientist.com... (10) http://www.newscientist.com... (11) http://www.skepticalscience.com... (12) http://en.wikipedia.org... (13) http://www.desmogblog.com... (14) http://www.newscientist.com... (15) http://www.realclimate.org...