Measuring solar output is problematic. We have in orbit the SOlar Radiation and Climate Experiment. (SORCE) Which measures radiation with wavelengths of solar energy from 1 to 3000 nanometers. Every few minutes the satellite measures the radiation directed towards the earth.

Unfortunately, as good as this is, this is still relatively inaccurate in giving the complete picture of solar output and variation.

Here's a link to the SORCE website which explains the technical limitations of measuring solar output.

All those who believe in "greenhouse gas" based global warming should read the above link.

We really don't know if that Total Solar Irradiance (TSI) 0.1 estimate is accurate at all yet. It was based on very incomplete measurements. The sun's output exists in such a stratified band of wavelengths that measuring only a portion of the band gives a very incomplete picture of TSI.

My 3% figure is a high-side guesstimate of the range of "estimated" TSI inaccuracy in measuring variability. I don't believe we've seen that much yet. I think we may already have seen .5-1% increase over the past twenty-five years. 3% is the nightmare scenario I hope we don't see, but suspect we will sometime within the next thousand years.

Such variance could happen sooner than anyone knows. We just don't understand enough about the sun to say for sure. Current theory puts forth that solar evolution of our sun, like all stars, will increase heat and radiation as the nuclear fuel runs out. The variability, speed and solar events which occur during this process are complete wild cards.

For all we know the sun may experience short but violent transitionary phases which could put out enough TSI to kill off every living thing on earth. I hope to heck not...but the dinosaurs' mass extinction could easily be explained by such a "TSI event".

It's good to think about this type of stuff. The sun is so important to life on earth and yet, ironically, we are unable to look directly at it without harm. It's almost as if life on earth is forced not to look at that which makes life possible.

And we all know - out of sight is out of mind. It's not surprising we feel we are the main force behind climate change when we don't look at the sun.