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

To: combjelly who wrote (753103)	11/16/2013 10:19:03 PM
From: Jorj X Mckie	2 Recommendations Recommended By FJB TideGlider Read Replies (1) \| Respond to of 1578342

Nonsense. There are lots of carbon sinks. Some of those sinks are biological, like trees, calcareous biological parts, bogs, etc. Others are physical, like the oceans. As long as we have had life, those sinks have never given up all of their carbon to the atmosphere. of course the carbon sinks have never given up all of their carbon. It's cyclical, not binary. The planet's apparent natural tendency to sequester carbon over long periods of time. Let unattended, it appears the planet is going to continue sequester carbon until very little is biologically active. In the billions of years there has been life on the planet, this has never happened. So I think your scenario is not based on reality. Like so much of your thinking. But, OK. Say that did occur. What would happen? In the perspective of human time, his comments are not nonsense. Back to, "it's cyclical"...but the cycles are significantly long that a period when the earth is a net carbon sink can seriously limit the amount of life that the planet can support, such that it can be detrimental to other organisms and especially humans. For the past 100 years or so, the planet has been a net carbon pump. That's a good thing. More food for plants. As you mentioned....it's called a "feedback" loop. But you are partially correct about a few things. The most significant being that the oceans play the biggest role in atmospheric CO2 levels. If there is global warming, the oceans become net carbon pumps and if there is global cooling, the oceans become net carbon sinks. Before the carboniferous period, atmospheric CO2 levels were very high.....double that of today. By the end of the carboniferous period, CO2 levels were at levels that are comparable to today. But if you look at the timeline, the change in CO2 levels can't be caused exclusively by the land (and shallow sea) carbon sinks (coal swamps). And as you pointed out (and I agree), if the carbon sequestration process of the coal swamps didn't cause the drop in CO2 levels, then burning the coal that was sequestered also cannot be the major factor in the rise in CO2 levels. The atmospheric CO2 level at the start of the carboniferous period was at about 600ppm. There were a couple of special conditions during that period that caused the carbon sinks to outperform the carbon pumps. Some of these are biological and some are geological. On a biological level, the animal and fungal diversity to break down the plant life of the period was not extensive. But more importantly, the existence of the super continent Pangea with a massive area of land covered by shallow slow moving water in warm climates created the perfect carbon sink environment....coal swamps. There were about 60million years where not only was the global average temperature declining, thus making the oceans net carbon sinks along with the coal swamps also sequestering land based flora such that we had double sink action. And still with CO2 levels around 210ppm for 70million years, the global temperatures were still significantly higher than today through the most of the Permian, Triassic and Jurassic periods. The majority of the carbon sequestration occurs because of biological activity. If biological activity were to significantly decline, per your scenario, carbon sequestration would also decline. Given that volcanoes aren't going away anytime soon, CO2 levels would start to climb. See where this is going? There are several incorrect assumptions here. Carbon sequestration is usually a combination of biological and geological processes. But it does get back to the cyclical nature of CO2. This is an example of what is called 'feedback'. All things being equal, it keeps a steady level of CO2. But what happens when all things aren't equal? In the geological record, we can see examples of that. One example would be those periods of heightened volcanic activity. More CO2 was poured into the atmosphere faster than the biological processes could sequester it. The results were spike in temperature and a wave of extinctions, up to 95% of species then extant. This is simply not true. The mass extinction event at the end of the permian has never been tied to any cause. There certainly is a lot of speculation though. But the spike in temperature associated with the end of the Permian was well under way and pretty much complete by the time the increased volcanic activity hit the stage, If anything, the aerosols from the volcanoes had a cooling effect. That further compromises the sequestration of carbon. Eventually, land-based plants adapt to the elevated CO2 and the accompanying elevated temperatures and start to sequester carbon at an elevated rate. As long as the rate of CO2 being released into the atmosphere doesn't accelerate, the CO2 level starts to decline. As the oceanic pH starts to increase, new organisms that form calcium carbonate can evolve and kick in that leg of carbon sequestration. Of course, that takes time. On a human scale, a great deal of time. The temporary sequestration of carbon in living organisms isn't meaningful to the climate. A plant grows, it gets eaten or dies and eventually releases its carbon. It's when the carbon is taken out of the life cycle that you care about. Though it all ends up back in the life cycle anyway. The calcium carbonate shells of the microscopic (and non-microscopic) organisms are eventually subducted and later released as CO2 from volcanoes. The fact is, the earth vacillates between being a carbon sink and a carbon pump on both macro and micro scales. The greatest determining factor for this is whether there is warming or cooling, not the other way around. There are other factors that contribute to the equation too. The natural phosphate sequestration cycle will limit the amount of life that can exist on the planet. The iron sequestration process also severely limits the amount of microscopic marine life that can grow and thus offset the processing of CO2 (did you know that the majority of the world's iron ore deposits are actually the result of the biological process of microscopic marine animals?). So the continued mining of iron ore and phosphates will both help to create more life with which more CO2 can be processed. My long winded point...there's a hell of a lot more at play than CO2 that has been released by man's activities.