August 13, 2013 at 1:11 am Suppose that the solar influence on global mean surface temperature, setting aside natural internal variability, varies as the time-integral of solar activity over the previous 11-year cycle.
Suppose also that the very small peak-to-trough difference in incoming solar radiance (it’s about 0.15% of total activity) were amplified sevenfold by cosmic-ray displacement, as Svensmark and many others think.
In that event, there could be half a Celsius degree of global cooling by 2020, and possibly more beyond that date, even after allowing for the small warming influence of CO2. The scare will not survive even seven more years without warming. Perhaps the end is in sight.
First his "half a Celsius degree of global cooling by 2020". You reckon?!
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| Data Source: NASA plus Monckton |
Next his "supposing" about cosmic rays. Galactic cosmic rays (GCRs) originate from outside our solar system. (In addition there are charged particles that come from within the solar system and the sun.) GCRs are affected by the solar magnetic field. The amount reaching earth is inversely correlated with the approximately eleven year solar cycle. So when the sun is least active, that's when more cosmic rays will reach earth. For a good short introduction to cosmic rays, you could start with the Neutron Monitor Database website.
For a detailed discussion of cosmic rays and clouds (ie effect on the climate), there is a detailed article by Jeffrey Pierce on realclimate.org.
One of the main notions put forward is that cosmic rays form clouds which reflect incoming solar radiation back out again. So if there is more cosmic radiation then there is more global cooling. Thing is, there hasn't been much variation in cosmic radiation in the past 50 years and more as discussed at realclimate.org by Jeff Pierce (above) as well as in an article by Rasmus E. Benestad - with the data presented graphically as follows. The grey dots represent cosmic rays but multiplied by -1 to emphasise the correlation with the solar cycle (in other words, they are the inverse of what is shown below).
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| A comparison between time evolution in the global mean temperature (dark red) and different solar indices (bottom) as well as CO2 forcing (green). All the curves here have been standardised, and the solar curves are shown along the bottom. The GCR are shown in grey, and have been multiplied by -1 to emphasise the correlation with the other solar indices. |
So there is nothing to suggest that the earth's current climate will be affected to a measurable extent by cosmic rays even if they were shown to play a part in cloud formation.
How would you spot a drop in temperature from "a low-activity sun"?
This next comment is from Dermot O'Logical who has the absurd notion that a drop of one whole degree Celsius would be lost in "natural variability".August 13, 2013 at 1:26 am @Kev-in-UK I think any drop in temps from a low-activity sun is not going to show up as a distinct signal – there are so many other factors in play with regards to surface temps.
Let’s suppose there is an actual effect of -1C over 10 years. How would you spot a 0.1C / yr effect amidst the noise of natural variability and be able to assign certainty to the cause being a quiet sun?
Here is what Dermot thinks would not be spotted "amidst the noise of natural variability"!
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| Data Source: NASA plus Dermot |
That's probably as cold as it's been in the entire Holocene. It wouldn't take much to notice that.
