September Beginners Tournament: Man and Global Warming

I affirm and thank 101 for this debate. == My case ==C1) Existence of a scientific consensus on climate changeThe scientific opinion on climate change is clear that mankind is probably the main cause of global warming. In fact, a survey has concluded that there are no scientifically relevant studies that provide a direct rebuttal to the idea that mankind is the main cause of global warming. [1] The IPCC, the American Meteorological Society, American Geophysical Union, and the American Association for the Advancement of Science all agree that the evidence for human-caused global warming dominating climate change is overwhelming and clear. [1] "That humans are causing global warming is the position of the Academies of Science from 80 countries plus many scientific organizations that study climate science. More specifically, around 95% of active climate researchers actively publishing climate papers endorse the consensus position." [2] A study by Doran (2009) found that 82% of climate scientists with a master degree or Ph.D agreed that mankind is the main cause of global warming. [3] NASA agrees, and notes that "most of the leading scientific organizations worldwide have issued public statements endorsing this position . . . Ninety-seven percent of climate scientists agree that climate-warming trends over the past century are very likely due to human activities." [4] A report written by 28 scientists representing 13 governmental agencies has stated, "The global warming of the past 50 years is primarily due to human-induced increases in heat-trapping gases." [5] C2) Human-induced increases in carbon dioxideAll scientists agree that carbon dioxide traps heat. That carbon dioxide traps heat is basic physics. Excess carbon dioxide traps heat. Harries, et al. (2001) finds "direct experimental evidence for a significant increase in the Earth's greenhouse effect" at the wavelength bands where carbon dioxide and methane trap heat. [6] The debate on carbon dioxide comes down to "climate sensitivity," defined as the increase in global land-sea mean temperature per doubling of carbon dioxide concentration in the Earth's atmosphere. All serious skeptical scientists and supporters of global warming agree that -- in a default state -- the climate sensitivity is likely 1.1 degrees Celsius. [7] The argument is about feedbacks. What are feedbacks? Feedbacks are mechanisms -- such as clouds and volcanic activity -- that amplify or dampen the effect that carbon dioxide has on temperature. The mechanisms that amplify the effect are called positive feedbacks, while those that dampen it are called negative feedbacks. [8] I argue that positive feedbacks dominate climate. Many studies agree. "Since the radiative effects associated with the buildup of water vapor to near-saturation levels and the subsequent condensation into clouds are far stronger than the equilibrium level of radiative forcing by the non-condensing GHGs, this results in large local fluctuations in temperature about the global equilibrium value." [9] This is demonstrated in the below graph: In simpler explanation, a feedback amplifies the effect of a forcing -- in this case, carbon dioxide. Using a Bayesian statistical approach, which is the "dominant" method in the literature, one can conclude that the average climate sensitivity is four degrees Celsius. [9] It is empirically demonstrable that climate sensitivity is at least three degrees Celsius. CO2 concentrations have increased from around 275 ppm to 400 ppm -- a 40% increase. This should manifest itself with a temperature increase of a little less than 1.5 degrees C. And temperature levels have increased precisely to this amount. [10] Below is a graph that showcases how much sensitivity different studies have found. [13] The following picture demonstrates the evidence that shows a climate sensitivity of around 3 degrees Celsius. It is well-known that CO2 levels are increasing. The below graph shows a direct rise in CO2 levels. [11] Much of CO2 increase is human-induced. "In pre-industrial times over the last 10,000 years, CO2 was relatively stable at around 275 to 285 parts per million. Over the last 250 years, atmospheric CO2 levels have increased by about 100 parts per million." [12] C3) Paleoclimatology suggests that mankind causes global warmingMultiple paleoclimate records suggest that CO2 has a direct effect on climate change. According to many studies, after the beginning of the Cenozoic Era 65.5 million years ago, carbon dioxide has been the dominant climate forcing. [14] The sun increased slightly over that time period, whereas temperatures cooled. CO2, however, fell steadily through that time period. An ideal example of this is the Vostok ice cores. "There is a close correlation between Antarctic temperature and atmospheric concentrations of CO2 (Barnola et al. 1987). The extension of the Vostok CO2 record shows that the main trends of CO2 are similar for each glacial cycle. Major transitions from the lowest to the highest values are associated with glacial-interglacial transitions. During these transitions, the atmospheric concentrations of CO2 rises from 180 to 280-300 ppmv (Petit et al. 1999). The extension of the Vostok CO2 record shows the present-day levels of CO2 are unprecedented during the past 420 kyr." [15] The below graph documents the correlation between increase in CO2 concentration and rise in temperature over 700,000 years. In fact, 2014 was the warmest year since 1400, suggesting that increased human activity drives climate change. Therefore, I conclude that human emissions increase temperatures, and, thus, mankind is the main cause of global warming. == Sources ==[1]: http://www.sciencemag.org...[2]: http://www.skepticalscience.com...[3]: http://tigger.uic.edu...[4]: http://climate.nasa.gov...[5]: http://downloads.globalchange.gov...[6]: http://skepticalscience.net...[7]: https://mises.org...[8]: Roy Spencer, "The Great Global Warming Blunder," p. 54[9]: http://www.giss.nasa.gov...[10]: https://www2.ucar.edu...[11]: http://www.esrl.noaa.gov...[12]: http://www.skepticalscience.com...[13]: http://www.skepticalscience.com...[14]: http://www.columbia.edu...[15]: http://cdiac.ornl.gov...