Global Warming is Largely Man-Made

In this debate I'm going to be arguing that Global Warming is anthropogenic.C1: Carbon dioxide causes warmingCarbon dioxide has been identified as having 'greenhouse' qualities for over a century[1]. The greenhouse effect occurs when GHGs allow shortwave solar radiation to pass through the atmosphere. This energy is absorbed of the earth, and then radiates this heat as infrared radiation. This is usually referred to as outgoing longwave radiation. This theory is particularly well-explained in this diagram. This means that a with more carbon dioxide in the atmosphere, we should observe lower levels of this longwave radiation escaping into space the the wavelengths carbon dioxide is meant to absorb. This was recorded by the IRIS satellite and later confirmed by the IMG satellite over a 26 year period. The paper concluded that the experiment could be considered "direct experimental evidence for a significant increase in the Earth's greenhouse effect"[2]. This same experiment has been adapted multiple times in order to measure downward longwave radiation from the ground[3][4]. This empirical evidence is unequivocal.Another way line of empirical reasoning that supports carbon dioxide's effect on the climate is through historic instances of climate change. This paper quantified the equilibrium temperature change in response to radiative forcing change, climate sensitivity, of the pre-anthropogenic eras[5]. The results of this analysis, were consistent with IPCC estimates. A 2 and 4.5°C global surface warming in response to doubled carbon dioxide.Just to really nail the coffin, I'll raise one further argument that determines a net positive feedback, in regard to climate sensitivity: modelling estimates. These work by calculating numerical data and predictions based on the physical, chemical and biological properties of its components, their interactions and feedback processes, and accounting for all or some of its known properties. A notable 2002 paper used a fingerprinting approach on modern temperature records and found a range of approximately 1.4 to 7.7°C [6]. A later model looked at paleontological data over the past 6 centuries to calculates a range 1.5 to 6.2°C [7]. This position is quite literally a platitude in any climate researchers books, since it is so well supported. This will be evident within my scientific consensus contention.[1] http://www.jstor.org...[2] http://www.nature.com...[3] http://www.agu.org...[4] http://www.agu.org...[5] http://www.nature.com...[6] http://www.sciencemag.org...[7] http://www.nature.com...C2: Humans are the source of the vast majority of resultant carbon dioxide This figure shows the estimated balance of carbon dioxide emissions.Despite man made carbon dioxide emissions being comparatively smaller than natural emissions, the real driving force of climate change is the net quantity of carbon dioxide released, since most natural carbon emissions are absorbed[1]. Because of this, atmospheric carbon dioxide is at the highest levels in approximately 15 to 20 million years[2]. Many skeptics claim that historically, carbon dioxide levels have been much lower, particularly around 500-600 million years ago[3]. But the carbon dioxide level is not the only factor that affect global temperature[4]. Additionally, this position fails to account for the differences in solar activity, that was drastically different from current levels. This position also fails to explain why a comprehensive analysis of carbon dioxide levels over the last 540 millions years concluded that "Periods of low CO2 coincide with periods of geographically widespread ice." This is clearly visible in this graph, where the shaded periods are periods of widespread ice. Many prominent climate science papers have argued that, if it were not for Natural contributions cooling the climate, we would be, in fact, a little hotter. Net human and natural percent contributions to the observed global surface warming over the past 50-65 years according to [6] (T00, dark blue), [7] (M04, red), [8] (S07, light green), [9] (LR08, purple), [10] (HK11, light blue), [11] (G12, orange), [12] (WS12, dark green), and [13] (J13, pink).[1] http://www.ipcc.ch...[2] http://www.sciencemag.org...[3] http://www.lavoisier.com.au...[4] http://www.ipcc.ch...[5] http://droyer.web.wesleyan.edu...(GCA).pdf[6] http://articles.adsabs.harvard.edu...[7] http://journals.ametsoc.org...[8] http://journals.ametsoc.org...[9] http://citeseerx.ist.psu.edu...[10] https://thingsbreak.files.wordpress.com...[11] https://thingsbreak.files.wordpress.com...[12] http://link.springer.com...[13] http://onlinelibrary.wiley.com...C3: There is a widespread, comprehensive scientific consensusThe contentions I have argued are not unfounded, flawed or bogus. In fact, they are so convincing that there exists a well-established scientific consensus.A recent survey of 12,000 climate science papers that expressed a position on the cause of global warming found that 97% of them agreed that anthropogenic global warming is occurring[1].The same survey found a historic strengthening of the Pro-AGW consensus since 1990. Another survey of 908 randomly selected climate scientists with more than 20 peer-reviewed publications settled upon a similar figure: "≈97% of self-identified actively publishing climate scientists agree with the tenets of anthropogenic climate change"[2]. My opponent might argue that the majority of papers expressed no position, therefore leaving room for a much weaker scientific consensus. This would fail to account, however, for the fact that the vast majority of papers included had already accepted AGW as a premise. Oreskes predicts this result, arguing that, "Scientists generally focus their discussions on questions that are still disputed or unanswered rather than on matters about which everyone agrees"[3].[1] http://iopscience.iop.org...[2] http://www.pnas.org...[3] https://www.lpl.arizona.edu...ConclusionI have shown that the climate is sensitive to increased levels of carbon dioxide, and that humans are the source of it. These positions are so well supported that an establish scientific consensus exists.Over to you, Con!