04 January 2008

Earth's Climate Still Driven by Sun--Film at Eleven

What exactly is the sun's connection to Earth's climate? It is quite important to find out the answer to that question, because without that knowledge all the effort going into "climate change" research, GCMs, and remediation will likely be wasted. Russ Steele runs a fairly new blog (less than a year old) called Dalton Minimum Returns. Over the past several weeks, Russ has provided a veritable treasure trove of information on solar cycles and solar science. In his post on 3 Jan 08, Russ points to a review article by Joanna D. Haigh at Imperial College, London, discussing the sun's effect on climate Earth. Quoting from Haigh's paper:
Changes in total solar irradiance undoubtedly impact the Earth’s energy balance but uncertainties in the historical record of TSI mean that the magnitude of even this direct influence is not well known. Variations in solar UV radiation impact the thermal structure and composition of the middle atmosphere but details of the responses in both temperature and ozone concentrations are not well established. Various theories are now being developed for coupling mechanisms whereby direct solar impacts on the middle atmosphere might influence the troposphere but the influences are complex and non-linear and many questions remain concerning the detailed mechanisms which determine to what extent, where and when the solar influence is felt. Variations in cosmic radiation, modulated by solar activity, are manifest in changes in atmospheric ionisation but it is not yet clear whether these have the potential to significantly affect the atmosphere in a way that will impact climate.

Further advances in this field require work on a number of fronts. One important issue is to establish the magnitude of any secular trends in total solar irradiance (TSI). This may be achieved by careful analysis and understanding of the satellite instruments involved in collecting data over the past two-and-a-half solar cycles, and must be continued through analysis of data from current and new satellites. For longer periods it requires a more fundamental understanding of how solar magnetic activity relates to TSI. This would not only facilitate more reliable centennial-scale reconstructions of TSI, from e.g. sunspot records, but also advance understanding of how cosmogenic isotope records may be interpreted as historical TSI.

With regard to the climate, further data-mining and analysis are required to firmly establish the magnitude, geographical distribution and seasonality of its response to various forms of solar activity. Understanding the mechanisms involved in the response then becomes the overriding objective. Current ideas suggest three main avenues where further research is needed. Firstly, the means whereby solar radiative heating of the upper and middle atmosphere may influence the lower atmosphere through dynamical coupling needs to be better understood. Secondly, it needs to be established whether or not variations in direct solar heating of the tropical oceans can be of sufficient magnitude to produce apparently observed effects. Thirdly, more work is needed on the microphysical processes involved in ion-induced nucleation, and, probably more importantly, the growth rates of the condensation nuclei produced.

Perhaps when these questions are answered we will be confident that we really understand how changes in the Sun affect the climate on Earth.
Dalton Minimum via Tom Nelson

Speaking of climate, Lubos Motl presents evidence of a most startling discovery: Instead of 2007 being the hottest year on record--as predicted by the orthodoxy--it was actually the COLDEST YEAR OF THE CENTURY!!! Both the post and comments are well worth reading.
via Tom Nelson

See SOHO and SolarCycle 24 for more images and information.

We are still waiting for Solar Cycle 24 to begin. A lot of solar scientists are beginning to fidget from impatience.

When looking for sunspots recently, I thought I had discovered a spot that may signal the onset of overdue solar cycle 24. Then I looked more closely, and saw that it was only a dark spot on my screen. Using nothing more sophisticated than a damp cloth, I washed the "sunspot" away! Que milagro, si? Actually, no. Just a part of a day in the life....

Seriously, much depends upon the solar connection to Climate Earth. Professor Haigh points out several questions that must be answered before any large scale efforts are mounted to mitigate "climate change." Otherwise, we may find the tail wagging the dog, or the cart pulling the horse.

Haigh is not a climate skeptic or heretic. She appears to be a mainstream climate scientist who just wants to understand the salient factors affecting climate--specifically radiative forcings.

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