Happy wrote on Jun 8
th, 2009 at 6:41pm:
muso wrote on Jun 2
nd, 2009 at 2:17pm:
Here you can see the effects of the Solar cycle on Solar irradiance. Look at the bottom 3 graphs.
You can see the regular changes amounting to about 2Wm-2. That's about 0.14% fluctuation, which is hardly substantial.
Incidentally, do you see how little the output of the sun has changed since 1978?
In a scale of Sun's output maybe it is substantial:
Quote:New Scientist 4 April 2009, page25
“The sunlight landing on Earth’s surface each day totals a whopping 120,000 terrawats, nearly 7,000 times the power currently used by all humans”
Comes out that humans use about 17 terrawats a day.
If Sun’s energy output fluctuates by 0.01% either way we get 12 terrawats more or less, depending which way it goes.
Hence lack of spots that lower the output of Sun’s energy can equal to all human activities many times over, ... interesting
Happy,
You'll have to explain that a bit more. The key factor is not the energy expended, but the CO2 (etc) released. All the heat comes from the Sun. As we add more CO2 to the atmosphere, it changes the heat distribution in the atmosphere, causing the troposphere to warm. Compared to the energy provided by the sun, human energy production is tiny. You've got that bit right.
I'm not sure if you were making a point beyond that, but at least you're trying to think it through.
Nobody was ever talking about the direct heat from Human energy use.