Anthropogenic Global Warming is a Threat

I accept. Pro asks me to begin arguments in the first round. I will assume a uniformitarian scale. I will argue against the resolution, not against GW per say. Historical Context: Global climate change (GCC) has been occurring for a long time [1]. Temperature measurements show that the Earth was much hotter in the past. This is evidently shown in the graph [1]. The Earth was also much colder in the past [2]. It occurred around 200,000-100,000 years ago. At these periods in time, humans were unable to emit greenhouse gases. Thus, GCC was not caused by humans. If GCC was not caused by humans then, it is logical to conclude that something else can cause it now. There is also the case of the medieval warm and cold period [3]. The planet was warmer in many places, and cooler in others. Vikings were able to settle Greenland and plantation of grapes in YorkShire occurred. There was also the case of the European coldsnap earlier this year [4], which made me think, "global cooling!" Current Global warming trend: Global surface temperature has increased by approximately 0.2 degrees celsius each decade for the past 30 years. [5] Effects: Rising sea levels: There have been a gradual rise in sea levels over the years [6], at about 3.5 mm/year. Glacier melting: There is evidence that glaciers have been melting ever since the last "little Ice age" of 1850. Greenhouse effect: What is a greenhouse gas? Methane, water vapor, Carbon dioxide, and ozone. The water vapor is easy to understand. As the Earth heats up, the oceans evaporate and vapors scatter into the air. Methane is harmful to the environment, but is not in such great quantities as Carbon dioxide. Carbon dioxide is my favorite, I produce it every second. Furthermore, atmospheric CO2 enrichment actually helps vegetation growth [7] by an almost 30% increase in productivity. Human activity supposedly linked to GW: Burning of fossil fuels: The usage of fossil fuels has a direct correlation with the rise of temperature. Conclusion: I do not dispute that the Earth is growing warmer. It was so much warmer during the time of the dinosaurs than now. This could not have been due to man. There were Ice ages. These were certainly not the result of man"s activities. The globe has been warming ever since 1850, the last mini ice age. It was warm several centuries before that. This shows that temperature is cyclic. I will now argue that there is a correlation between human activity and the current rise in global temperatures. If we plotted a graph showing how much greenhouse gas humans emit through their activity, alongside a graph of the rise in sea levels, and a graph of temperature rise for whatever data we have from 1850, the correlation is obvious. Now I will contend that human activity is not the cause of rise in temperature. No experiments has been made to prove this. If there was, I would like to know which other planets were used as experimenting ground. 1. http://www.grida.no... 2. http://geography.about.com... 3. http://www.skepticalscience.com... 4. http://www.huffingtonpost.com... 5. http://www.pnas.org... 6. http://www.skepticalscience.com... 7. http://www.sciencedirect.com...