CO2sceptics News Blog | Solar Variations: Too Tiny to Matter?
Update 1: See the comment section for this post for a reply from Bill Chameides.I have seen your commentary on the influence of solar variations on climate. It is counter-consensual, for most solar physicists ascribe more than a minuscule influence to solar forcing. Your argument concentrates on the last two or three solar cycles: however, that is not a sufficient period to show the whole picture. During the Maunder minimum, between 1645 and 1715, there were no sunspots, and both the Hudson and Thames rivers were prone to freeze over during the winter months. Between the end of the 70-year Maunder Minimum and the end of the 70-year solar Grand Maximum that ended in 1998, there had been an inexorable and near-monotonic increase in solar activity between the peak of one 11-year cycle and the peak of the next (see the graph illustrating this point in Hathaway et al., 2004)...
Update 2: And now Lord Monckton has posted a comment in reply...
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2 comments:
Lord Monkton,
Did you actually read my post? I most certainly did not ascribe a "minuscule influence to solar forcing" on climate. Here is what I did say, verbatim: "Of course the sun affects climate and there is little doubt that variations in the sun's energy (called the total solar irradiance or TSI) have caused significant climate swings in the past. For example, the so-called Little Ice Age, an anomalously cold period that peaked in the 1600s, may have been caused by an extended interval with low TSI."
The post was specifically focused on the warming over the past 30 years. I don't think the Maunder Minimum had much to do with that, do you? And if not, why bring it up? And as the figure in my post clearly shows, there has not been an inexorable rise in total solar irradiance over the past 3 solar cycles. Solar forcing is not the explanation for the warming over the past 30 years.
What about sunspots? If you want to find out, check out my future post on the subject at www.TheGreenGrok.com.
Bill Chameides
Chameides did not do me the courtesy of reading my email. I did not say that he had ascribed a minuscule influence to solar forcing compared with 1750, but that the IPCC had done so, from which it followed that the IPCC could not explain the seven years of global cooling that have taken place since late in 2001. I note that Chameides is silent on that notable cooling, which of course follows the end of the recent solar Grand Maximum, during which solar activity was greater than at almost any similar period in the past 11,400 years.
He has also carefully avoided answering my main point - that, between the end of the 70-year Maunder Minimum 300 years ago and the end of the 70-year solar Grand Maximum in 1998, solar activity had increased near-monotonically, and that global temperatures had responded by increasing at 0.5 K per century for 300 years.
The uptick of 0.25 K over and above this long-running warming rate in the last quarter of the 20th century has been entirely canceled in the first few years of the 21st. Over and above the long-run warming rate, which was established 250 years before humankind could possibly have had any appreciable influence on climate, there is now no detectable anthropogenic signal in the global temperature datasets at all.
Solar forcing, whose effect is moderated and delayed by the oceans, has certainly been a very substantial contributor to temperature changes over the past 30 years: that is the significance of the solar Grand Maximum, which Chameides is careful not even to mention.
Chameides has also carefully avoided answering several other points in my carefully-considered and quite well-referenced email. I regret the disfiguring, ad-hominem tone of some of his remarks.
Perhaps Chameides would do me the scientific courtesy of answering my original email fully and, this time, entirely ad rem. - Monckton of Brenchley
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