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Politics : The Environmentalist Thread -- Ignore unavailable to you. Want to Upgrade?

To: DavesM who wrote (21608)	5/15/2008 10:11:00 AM
From: neolib	Read Replies (1) \| Respond to of 36917

Are you sure you know what you are supposed to be looking for? Follow the thread back and you will see that I pointed the period issue out already. I was not the one claiming that a spike on the top of a particular solar cycle could change a year-year global temp. That spike is most likely all of a few days or a week+ long. It was laughable that it could have any effect on global temps. But for the heck of it I played along. What you should note from that graph is that there is NO correlation between the cycles themselves (either the amplitude of their broad peaks, or the rise or fall, i.e. phase) and any response in temps. So that gets us back to the period issue. As I pointed out, there are some graphs floating about claiming impressive correlations between some normalized period metric and the global temps. Unfortunately, said graphs have a bunch of nonsense in them. When it suits them, shorter periods produce higher (or is it lower?) temps, but then a "phase reversal" happens, and the correlation reverses, so that longer periods now produce higher temps. So having stitched together a graph in this fashion, what does it mean? Not much IMO. The further problem for the period crowd, is coming up with a physical basis for how period can affect temperatures at all. Remember that the solar output varies only weakly during the solar cycle anyway, so the only mechanism likely to be affected by period variation would be if some process on the earth was highly resonant right at this frequency, and the slight energy change with changing frequency was caused significant amplitude variation as a result of being in resonance or off resonance. Something like that. Indeed, there does seem to be changes in the peak number of sunspots per cycle, I just don't know if the study looked at that - do you? The reconstructions are showing cycles averages I think, so more like the area under each curve, not the peaks. The values reported were further mapped to 10-years, which is not a cycle, so I think there might be some issues there. They claimed they could not reconstruct yearly values, but thought they could get cycle averages. What I see in the graph I posted is that the higher peaks are sometimes shorter cycles, so that looks like the cycle average then smears out differences?? There have been only a few papers on such reconstructions, and the papers claim conflicting results. There was a note in Nature claiming that in the last 600 years there were higher results than at present (all IIRC!). These papers are 2004-2005'ish, but I suspect more data will eventually result in more papers. 3. I believe that the authors re-examined the data (adding points in the late 90's) and found that there was a divergence to sunspot period and temperature in later time points (meaning when CO2 remained relatively constant, temperature followed sunspot cycle period) - of course, there is currently a divergence between CO2 and temperature (but that is being explained by another oscillating input). The problem is that solar output, and sunspots as well, have not changed much (or weakened slightly) since the 1950-1960 and present. Go look at my graph again for the sunspot case. The cycle with 1960 was the biggest, the ones since have been significantly lower. And it is the time since then that has seen temp increases. See this chart which is an attempt at attribution of climate change by source. Note the solar component, which although it wiggles about, is not changing much since the 1930's.