I have heard some try to argue that. But if you do the math, earths surface temp (average) is around 290K (Kelvin). Sorry I do not know exactly what the average temp of the earth is at this time and do not have time to look it up. But this is close enough for this argument.
So if the surface of the earth would be around 10K if there were no sun then you have a delta of around 280K because of the sun. 0.1% is a .28 K difference IF TSI was the ONLY thing that mattered.
For those who don't know the conversion 0 Celsius is 273 K or Kelvin. 10 Celsius is 283 Kelvin. 0 Kelvin is absolute zero. So a difference of .28 K is also a difference of .28 degrees Celsius for a 0.1% difference in TSI.
Why this is ignored or called irrelevant I do not know or understand. Yes I do know that it is not as simple as only TSI. Many many things are now know to be significant factors and in some cases possibly stronger than varying the TSI. they use the percentage because people have been conditioned to see a small percent or any percentage less than 1 as being irrelevant... So in other words a lie without lying.
The average TSI of the Sun from high to low of the solar cycle is shown here (for the last 3 cycles)
http://en.wikipedia.org/wiki/File:Solar-...
The number went from 1365.5W/m2 (low) to 1366.5W/m2 (high) a difference or ~1W/m2 so the number would actually be less then 0.1%. What you seem to be trying to ignore is that this is a short term change it rises and falls in the space of a few years over the 11 year cycle, if it was a longer effect it may have some effect as it seems to have during the LIA which was not a few years but lower activity for ~70 years. Deniers seem to have this sad wish we will have another Maunder Minimum, as they seem to have this fantasy that this in some way will disprove AGW. The Sun is an outside influence we have no control over but that doesn't change the effect of Co2 or AGW in anyway, yes the Sun could override the effect but if Co2 is still rising we would see a rapid rise in temp at the end of such an event and in fact we have already warmed the planet as mush as the Maunder Minimum is thought to have cooled it.
Carbon dioxide is currently 0.039% (of the total atmosphere) a point deniers like to make, to make Co2 sound insignificant, yet what deniers don't like to mention is that all the greenhouse gas (including water vapor) make up ~1% of the total atmosphere on that scale Co2 is more like 4% of the total greenhouse gas atmosphere and pound for pound a stronger greenhouse gas than water vapor with a roughly averaged 'effect' of ~10% of the greenhouse effect, a number that scares deniers so they bend the facts are try to reference it by volume rather than effect and against the entire atmosphere rather than the part that counts. That 1% of greenhouse gases, raises the planets temperature ~30c, 10% of which would be ~3c we have raised Co2 almost 40% which would be a little above 1c and in fact temperature has gone up about 1c.
The rise in Co2 is there all the time unlike the brief rise and fall of the solar cycle, it may also, from time to time be overridden by an exceptionally strong El Nino or low PDO (as it was in the 1940's) but the current PDO seen to be having far less effect, through it all Co2 is there slowly nudging temps higher.
http://en.wikipedia.org/wiki/File:PDO.sv...
They would claim it's irrelevant or has no impact because to claim otherwise would be sacralidge. It's probably part of some kind of wierd scientific principal that only applies to AGW theory. Like the principal of credibility through association, gravity is science too. I imagine their theory goes something like this.
The earth only receives .0000001% of the suns energy and an increase in the suns output by .1% would have no impact.
The TSI has changed by less than 0.1%, the amount of CO2 in the atmosphere has increased by about 40%, does that answer your question?
I don't think any scientists say that the sun's TSI is irrelevant.
EDIT to Refute Kano's misleading statement: (to be generous) Kano said "...man share of Co2 say 0.02%."
Human emissions more than account for the 40% increase in the amount of CO2.
No one says that the Sun has no effect on climate. The reason why scientists don't believe that the Sun is responsible for the warming since the 1970's, is that solar activity has been trending in the wrong direction.
http://www.woodfortrees.org/plot/gistemp...
Which explains why 2010 was warmer than 1710, but not why it was warmer than 1970.
edit
Co2 is not carbon dioxide. It is a diatomic cobalt molecule.
Dave H
Yes, sunspot numbers are just a proxy of solar activity. Unfortunately, the TSI data available on woodfortrees only goes back to the late 1970s.
http://www.woodfortrees.org/plot/gistemp...
Nevertheless, Sunspots can be shown to be a very good proxy for TSI.
You pay me $20,000 and I'll set up a website with such capabilities.
Regarding your link, please read my response to the statement about 70 years of intense solar activity.
CR.
I'm wondering why you posted a chart of sunspot numbers, and why on earth would you put a linear trendline on it? You could at least have used an 11yr running average.
You get a diffent story if you take a longer view of TSI.
http://farm9.staticflickr.com/8385/86504...
Edit Kano. The link I was referring to was the one from Climate Realist. His woodfortrees chart showed data from the sunspot index, not TSI.
Which will change the appearance of a jug of water more: a .1% change in the amount of light coming from the light bulb illuminating the room, or a 40% change in the ~.039% of the contents of the jug that is dye instead of water?
For one thing, they are two different measures: (1) a percent / change [in something] and (2) and a percent / volume [in something else].
Second, I doubt that anyone has actually tried to make that specific comparison - because there is nothing that can be made from it.
of 0.1% change is irrelevant, being so small as not being able to change Earths climate, while Co2 is 0,039% and has a big influence on climate?
