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Politics : Formerly About Advanced Micro Devices -- Ignore unavailable to you. Want to Upgrade?

To: Taro who wrote (1060020)	3/12/2018 5:07:35 PM
From: Land Shark	Read Replies (1) \| Respond to of 1571927

We weren't around 600,000 years ago to drive that sort of climate change. Other factors were in play... such as wobbling of the Earth's orbit. You're comparing apples to oranges. To quote the article you posted from skepticalscience.com (which refutes your position)... "A 2012 study by Shakun et al. looked at temperature changes 20,000 years ago (the last glacial-interglacial transition) from around the world and added more detail to our understanding of the CO2-temperature change relationship. They found that: The Earth's orbital cycles triggered warming in the Arctic approximately 19,000 years ago, causing large amounts of ice to melt, flooding the oceans with fresh water. This influx of fresh water then disrupted ocean current circulation, in turn causing a seesawing of heat between the hemispheres.The Southern Hemisphere and its oceans warmed first, starting about 18,000 years ago. As the Southern Ocean warms, the solubility of CO2 in water falls. This causes the oceans to give up more CO2, releasing it into the atmosphere."

To: Taro who wrote (1060020)	3/12/2018 5:18:48 PM
From: Wharf Rat	Read Replies (1) \| Respond to of 1571927

‘Historically, CO2 never caused temperature change’–Not so By Coby Beck on Dec 29, 2006 (Part of the How to Talk to a Global Warming Skeptic guide) Objection: In the geological record, it is clear that CO2 does not trigger climate changes. Why should it be any different now? Answer: Given the fact that human industrialization is unique in the history of planet earth, do we really need historical precedent for CO2-triggered climate change before we accept what we observe today? Surely it is not far-fetched that unprecedented consequences would follow from unprecedented events. But putting this crucial point aside, history does indeed provide some relevant insights and dire warnings. During the glacial/interglacial cycles, temperatures and CO2 concentrations showed remarkable correlation. Closer examination reveals that CO2 does not leadthe temperature changes, but lags by many centuries. Even so, the full extent of the warming can not be explained without the effects of CO2. Though these cycles do not demonstrate that greenhouse gas initiated warming, they do lend credence to the importance of CO2 and CH4 in setting the planetary thermostat. There are also events in geological history when sharp rises in temperature were initiated and driven by large spikes in greenhouse gases — not unlike the fossil-fuel-emissions spike today. The Paleocene Eocene Thermal Maximum is such a case. Roughly 55 million years ago, ocean pH levels dropped drastically and global temperatures rapidly rose over 5oC. The resolution of available proxy records indicates that this occurred in a period of time no longer than 5K years; it’s not possible to know if it happened even faster. The likely cause was massive releases of methane from the ocean floors, perhaps due to some smaller warming or changes in sea level. It took over 100K years for the ocean, atmosphere, and temperatures to return to their previous state. The result was a mass extinction event that took millions of years to recover from. We can also look at the formation of the Deccan Traps. In this case, a massive and sustained volcanic action altered atmospheric chemistry and caused a drastic climate change, one that lead to the extinction of the dinosaurs. And Snowball Earth theories involve the build-up of greenhouse gases as the mechanism by which the earth eventually escaped its frozen state. In short, it is simply untrue that history lacks precedent for greenhouse-gas-driven warming. The precedents are there, as are the dire warnings. grist.org