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Politics : Mainstream Politics and Economics -- Ignore unavailable to you. Want to Upgrade?

To: Wharf Rat who wrote (2692)	9/24/2011 10:02:18 PM
From: FJB	5 Recommendations Read Replies (2) \| Respond to of 85487

The following summarizes levels of CO2 under various conditions: 40,000 ppm: The exhaled breath of normal, healthy people. 8,000 ppm: CO2 standard for submarines 2,500 ppm: CO2 level in a small hot crowded bar in the city 2,000 ppm: The point at which my CO2 meter squawks by playing Fur Elise 1,000 to 2,000 ppm: Historical norms for the earth's atmosphere over the past 550 million years 1,000 to 2,000 ppm: The level of CO2 at which plant growers like to keep their greenhouses 1,000 ppm: Average level in a lecture hall filled with students 600 ppm: CO2 level in my office with me and my husband in it 490 ppm: CO2 level in my office working alone 390 ppm: Current average outdoor level of CO2 in the air 280 ppm: Pre-industrial levels in the air, on the edge of "CO2 famine" for plants 150 ppm: The point below which most plants die of CO2 starvation

To: Wharf Rat who wrote (2692)	9/25/2011 4:53:10 AM
From: Jorj X Mckie	3 Recommendations Read Replies (1) \| Respond to of 85487

I'm cool with that. I am a strong believer in man made CO2. I know it exists. I know we have created a bunch of it. Though, whether you can blame all of the increase on humans is up for some debate, but I'll give it to you. The EPICA ice cores show something very interesting. I got this chart from here: realclimate.org Notice how there are pretty regular spikes in CO2 levels that correlate very nicely to the end of glacial periods and mark the interglacial periods? Now this chart doesn't show the last 100ppm in the last 150 or so years. Which, as many point out, is a pretty significant increase. The key here is that this spike in CO2 is only remarkable in that the last 150 years have been at a significantly higher rate and has reached higher levels than before. Ok...we are all on board with that. But did you notice what happens once CO2 levels stop spiking? I'm sure you can look that up on your own (hint, end of the interglacial period). But let's look at something else from the EPICA ice core. Look back about 130kya. Note the temperature spike that is 3+C greater than current levels. What does that tell you? It tells me that there are influences beyond CO2 that can affect the global average temperature. What we can see,and I include you in this, is that CO2 levels are definitely higher than what would be considered "normal cyclical variations". But that temperature levels are well within normal cyclical variations. I don't see how we can disagree on this unless you want to discredit your own reference of the EPICA ice cores. (BTW: if you go back 410kya or so, you will see that the temps have been at least 2C higher than current temps a total of 4 times.) I think you also have to agree that the EPICA ice cores are giving a pretty strong indication that there is a glacial/interglacial cycle that can be correlated to CO2 and temperature levels. I think you also have to agree that there is a pretty strong likelihood that we are at the end of the interglacial period and that the next glacial period is right around the corner. The thing that the charts don't show is causation. What they show is correlation. Yes, CO2 has a GHG effect. But how much? Considering the spike in the CO2 level, if there was a direct causal relationship, the temperature should be well above what it was 130kya. N'est-ce pas? Instead, temps are significantly lower. Presenting CO2 data without the corresponding temperature data does nothing to further the AGW argument. Can you show me that our current global average temperature is outside of normal cyclical variations?