Sunspots, a Crucial Climate Indicator
Posted on April 12, 2009 by chillguy33
Commenters on this blog (Julia LeVan on Human CO2 Snuffs Out Sun’s 10.7cm Band) have noted that anthropogenic carbon dioxide may be unlikely to affect conditions on the sun. This is an important insight which may have a lot of truth in it, notwithstanding the likely resistance of climate scientist and global warming pundit and businessman Al Gore. Particularly since conditions on the sun are seemingly of primary, if not dominant, significance in Earthly climate.
Dr. Willie Soon, a senior Harvard astrophysicist, has observed that “when sunspots are present, the temperature goes up; and when sunspots are absent, the temperature goes down.” It may be disputable I suppose, but I think Dr. Soon is referring to temperatures on Earth, actually.
Dr. Soon goes on to further ignore (or perhaps minimimize is fair) the importance of carbon dioxide in controlling Earth’s climate, in this most interesting article, Harvard astrophysicist: Sunspot activity correlates to global climate change
H/T: ICECAP ‘Curious’ Why the Sun Has Been So Dim Lately, under category Blogosphere
Further quoting Dr. Soon, and his explanation of three rather direct ways in which solar output could have dominant influence on terrestrial climate:
“When the energy input to the Earth from the sun is lower, you can easily imagine then what the first effect would be — heating less of the ocean’s surface. This promotes less evaporation of water vapor from the ocean, reducing what we all know to be the major green house gas, water vapor, in contrast to atmospheric carbon dioxide. Then, you would say that if the sun provides less energy to warm the ocean’s surface, and there is less of this water vapor and less of the water vapor greenhouse effect, then the Earth begins warming less so than you would normally have during the normal sunspot activity maximum when the sun gives off more light-energy to the planetary system.
“The second way to think about this is if the sun is giving less light to the ocean’s surface, then you will also give less energy to transfer the heat, or even the material itself, from the surface to the upper atmosphere. The connection between the surface and the upper atmosphere is less than it would be, including the circulation patterns of the weather and the oceans.
“And then one can think about it another way, if you give less energy to transfer energy from the surface to higher up in the atmosphere, as high as 5 or 8 kilometers, then the chance for the system to produce these so-called thin high-cirrus clouds is less. These are the clouds that are very, very effective as a greenhouse blocker, these thin high-cirrus clouds. This is the idea that Professor Dickenson from MIT has suggested, that the Earth system may act like an iris. If it’s too warm, then the iris opens, if it’s too cold it closes, so that this fixture can trap heat, providing a very efficient way to warm or cool the Earth system.
“During a solar activity minimum, imagine that you produce less of these high-cirrus clouds, then the ability of the Earth to shed heat itself is a lot easier, therefore the system cools. And then continuing, when you don’t have enough energy to bring all of this water vapor and the currents more than a few kilometers up, then it all accumulates at the bottom of the system, producing more of the low clouds. And on low clouds we know that they are very effective at reflecting sunlight. So again, it’s another way that the Earth system can cool.
“And even another way to think about it is less energy intercepted in the tropical region, from say 20 or 30 degrees north and south latitudes, then you are able to transfer less heat energy to the polar regions, resulting in the arctic regions getting slightly cooler in that sense as well.
“So these are some of the possible scenarios that we’ve reached which in sort of a low-sunlight scenario would affect the Earth’s weather.”
Dr. Soon does not give much notice to carbon dioxide of any kind. He is also not a strong advocate of the “chilling stars” theory of Dr. Henrik Svensmark and others apparently; but his thoughtful explanation of three distinct and very reasonable mechanisms by which solar conditions strongly influence Earth’s climate is very noteworthy.
“If this deep solar minimum continues and our planet cools while CO2 levels continue to rise, thinking needs to change.”
Or even if the deep solar minimum does not continue (but our planet continues to cool while CO2 levels continue to rise).
Interesting WBZ-TV video here: ‘Curious’ Why The Sun Has Been So Dim Lately.
Filed under: Willie Soon | Tagged: Willie Soon