The Motley Fool Discussion Boards
Miscellaneous / Climate Change
|Subject: Re: IT's all a scam! Gov't comes clean||Date: 9/7/2013 3:38 AM|
|Author: AstroPhool||Number: 44844 of 47112|
The "harmful solar rays" being referred to are high-energy electrons from the solar wind. These electrons *never* reach the Earth's surface, whether the solar wind is active or not.
Ajax: No. UV radiation from the sun is not electrons. UV radiation is very energetic shortwave radiation.
I was actually referring to telegraph's original post. His comments come from an InvestorVillage post that links to article #163 on PSI:
which is about this NASA release:
This article describes the heating of the upper atmosphere by a large flare (a coronal mass ejection). These flares heat the atmosphere mainly from the absorption of charged particles (mainly electrons) from the solar wind. This is the same process that causes the aurora, which is why I mentioned it in my post. The CO2 (and NO) emission referred to here is from these gases in the upper atmosphere being heated by energetic electrons from the solar wind (as enhanced by the solar flare). If you had infrared-sensitive eyes (and you were above the lower atmosphere), this emission will look very similar to that of the aurora. This upper atmosphere heating is not caused by ultraviolet radiation from the sun, although the amount of UV radiation reaching the Earth does increase with solar activity.
On the other hand, Ajax is referring to a different PSI post:
about CO2 absorbing more incoming solar radiation than outgoing emission from the Earth:
Indeed. Alarmists are obsessed with CO2 blocking longwave radiation from leaving the planet and ignore the fact that the same CO2 is now blocking longwave solar radiation from coming in! In other words this knife cuts both ways.
This is a completely separate issue because now we are talking about CO2 in the lower atmosphere (mainly in the troposphere). It isn't true, either. From that PSI article:
While we have been told that 'greenhouse gases' are a cause of dangerous surface global warming, climate scientists have failed to tell us that they also absorbs radiation from the Sun in the upper atmosphere thereby protecting the Earth in a similar fashion to the protection given by ozone.For the case of absorption by CO2, the most prominent spectral line is at a wavelength of 4.3 microns.
Applying Planck's Law this gives us a spectral radiance of no more than 0.73 Watts per (steradian metre squared) per micron. This is for an Earth emitting at a temperature of 288 degrees Kelvin, dependent on the emissivity at the time. For the incoming Sun's spectral radiance at the Earth's orbit, the figure is 2.24 W/(sr m^2)/micron for a Sun temperature of 5780 degrees Kelvin.
These numbers mean that at least THREE TIMES as much heat is radiated back into space by CO2 in the upper atmosphere as is 'back-radiated' to the Earth's surface at this wavelength.
Clearly, absorption and re-radiation of the sunshine in the upper atmosphere at this wavelength cools the Earth and is going to cause additional cooling as the concentration of CO2 increases.
I haven't gone back and checked these numbers but they are probably right -- as far as this argument goes. The problem here is that the important CO2 band blocking thermal emission from the Earth is not the one at 4.3 microns mentioned in the PSI article, but the 15 micron band. Here the amount of absorbed solar radiation is very small, but the radiation form the Earth's surface is large. The argument made by the PSI article (and Ajax) is false. Most of the energy from the sun is contained between 300 nm and 4 microns, and most of that reaches the Earth. Outgoing radiation from the Earth mostly lies between 4 and 40 microns (so there is almost no overlap with the incident solar spectrum), and most of this is absorbed to some degree by the Earth's atmosphere. The end result -- little incoming solar radiation is absorbed by the atmosphere, but a large fraction of outgoing thermal emission from the Earth is absorbed, and this hinders the radiative cooling of the Earth. This is the greenhouse effect.
Spinning already posted this link to globalwarmingart.com, but it's so useful that I'll post it again here:
It shows immediately that there is little overlap between the solar spectrum and thermal emission from the Earth. It also shows where the important molecular bands are in the infrared. This figure says it all.
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