The comment section below is an archived discussion, please do no edit it. Start a new discussion should continuing be necesary. ~~Myotragus
Global warming: everyone talks about it, everyone believes it. But have you ever stopped to consider the facts? I am about to squash the theory of man made global warming without a doubt, and without a single disagreement.
So, here is a summary of the theory of global warming. It states that after the industrial revolution, humans have caused an increase in the amount of carbon dioxide in the atmosphere. This carbon dioxide has caused temperatures to rise since the 19th century, and is melting the Arctic and Antarctic ice sheets. This is based on a number of true facts. These are: carbon dioxide levels have risen from 280 ppm to 380 ppm since the industrial revolution; temperatures have risen about 1.5ºC since the industrial revolution, depending on the source this may vary from 1ºC to 2ºC; and the somewhat obvious melting of the ice sheets. They got these all right. But the one thing they got wrong was the connections. What if this carbon dioxide has little to do with the rise in temperature?
Now, to figure out whether CO2 is always connected to temperature, we'll have to look at prehistoric documents. Since we live in a glaciation, it's best to look at other glaciations to tell. The Cryogenian glaciation is connected to CO2 loss in the atmosphere, but all of the other glaciations are not linked to carbon dioxide concentrations. The Karoo glaciation is linked to the formation of Pangaea, and nothing is shocking with the carbon dioxide levels, so this doesn't prove anything. However, looking at the Andean-Saharan glaciation, we can see that carbon dioxide does not necessarily have to do with greenhouse gas levels. At the beginning of the period, the sea temperatures averaged 45ºC, making the Early Ordovician perhaps the hottest time period in Earth's history. By the end of the period, however, a glaciation was underway. The shocking thing here is that during the entire period, the temperatures went from 4000 ppm to 3000 ppm. The usual explanation for this is that the sun was 4% dimmer, and in that case, CO2 has little influence on climate. So, now that we know carbon dioxide does not necessarily cause climate change, what is?
We live in an interglacial, and interglacials have the most variable temperatures of all climatic periods. All of these great changes in temperature are due to Milankovitch cycles, not drops in carbon dioxide or the brightness of the sun. This can be proven because the apparent glaciation threshold during the Cenozoic has been 500 ppm of carbon dioxide. However, during the Neogene the carbon dioxide was under this threshold and no glaciations occured. Also, even though the Andean-Saharan glaciation was caused by dropping CO2, this shows that carbon dioxide has little to do with climatic change, because a 4% difference in the brightness of the sun was important enough to make the glaciation threshold six times higher. Also, this apparent threshold, even if lower than 500 ppm, does not exist, at least during this glaciation, because today, the temperatures are as high as in the Pliocene, yet we are still in a glaciation. In any case, the sun obviously has much more influence on climate than CO2 does, even if we have no threshold today. All evidence points towards a cause of the Quaternary glaciation unrelated to carbon dioxide levels, almost definitely Milankovitch cycles.
Now, most estimates as to how long the Holocene interglacial will last, including the past 12,000 years, range from 20,000 to 26,000 years. And although the Holocene climatic optimum (the highest temperature during the Holocene) is thought to have occurred from about 7000 BC to 3000 BC, true climatic optimums happen during the middle of the interglacial. The Earth has just gone out of the Little Ice Age stadial, and now the temperature is rising after that cool period. And we are just about halfway through the interglacial. Therefore, we are heading towards the natural climatic optimum of the Holocene. As for the recently increasing carbon dioxide levels? They are caused by humans, but have no effect on the climate whatsoever.
There it is – man made global warming disproved. It is all due to the great climatic swings in the Holocene glaciation, not some wild theory as to how we are causing the sea level to rise by hundreds of feet. And so man has done no wrong, and this is no more than the natural course of history.