Pretty soon you'll realize that the math which is required is "NOT easy".
I think it was Einstein that said "Make things as simple as you can, but no simpler than they are"
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Oh my! I didn't realize this was a 19-page thread already! I'm sure my point has already been better argued. My apologies!
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It's actually very simple, conceptually.
There are three fundamental ways to alter the Earth's energy balance:
1. Change solar output
2. Change the average distance* between the Earth and Sun
3. Change the atmosphere
It's very obvious that atmospheric greenhouse gasses have major impacts on Earth's climate; we're not the moon! If you want to see how climate looks when no atmosphere exists to scatter incoming shortwave radiation and absorb outgoing longwave radiation, look at the moon. The greenhouse effect is very well established. It is the default consequence that increasing greenhouse gas concentrations will increase the greenhouse effect, and it's well supported by simply and complex modeling alike, as well as millions of years of paleoclimate data.
For any fence sitters and/or lurkers, it should be noted that mhaze's conclusions are at odds with essentially all of Earth science. Really. Pick up any intro to Earth science text book published in the last couple decades, and anthropogenic climate change will be addressed. It's literally text book stuff. Almost zero peer-reviewed research supports mhaze's conclusions. About a month ago I attended the massive AGU fall meeting (10,000+ Earth scientists from around the globe!) and mhaze's views were predictably absent. Rather, numerous oral and poster sessions were dedicated to climate change and its impacts on the biosphere, the hydrological cycle, and water, food, and energy security.
*More complex than simple distance, but it's a fine way to imagine it for these purposes...