I didn't get into where all the data and simulations come from.
Once upon a time I was a climate researcher for the DOE, by the way. These kind of things can be easily manipulated to show what you want to show. That's not to say I don't believe CO2 emissions are the primary culprit. I do. I'm just saying it's not something that really can be proven, one way or the other.
For instance, the "simulations" are assuming different factors have different strength influences. The strongest one, for CO2, for instance, is based on looking at historical (over hundreds and thousands and even millions of years) CO2 concentrations and comparing to known temperature anomalies. From that you get a forcing factor, which is inputted into the model. It tells you that historical temperatures are well correlated to historical CO2 concentrations. And that's true.
But.... Determining which is the cause and which is the effect. That's a horse of a different color. The models assume the CO2 as the cause and the temperature as the effect. But it could be reversed. Or they both could be caused by another factor not yet found. For instance, with warming temperatures, ice retreats, releasing enormous amounts of methane and CO2 trapped in tundra. Which warms the earth more, which melts more ice.... So both cause and effect here! As another, most of the earth's CO2 is trapped in the oceans. It gets trapped in downwelling areas, which are driven by ice formation in polar regions. As ice forms, the remaining surface water becomes more saline, and resistant to freezing. Saltier, colder water is denser than the less salty, warmer water below. And hence it sinks, taking CO2 with it, and it won't come back up again for another 500+ years. The reverse happens in equatorial regions, where deep water warms and rises giving off it's CO2. Well, a warming earth corresponds to poles warming more than equatorial regions. Hence downwelling (trapping of CO2) near polar regions is slowed while upwelling is not. i.e. warming CAUSES more CO2 in the atmosphere, rather than vice versa. You could argue the higher CO2 during warmer periods is an effect, not the cause.
Anyway, that just speaks to the vast levels of uncertainty in it all. The above is just scratching the surface. Too many variables. Literally thousands of positive and negative feedback mechanisms and we have them poorly sorted out. I do believe anthropologic CO2 emissions are at least one of the primary causes of the observed warming over the last 100 years. I just don't pretend I, or anyone else, can absolutely prove it beyond the shadow of any doubt.
The one thing I will fully criticize here, though, is the mishandling of the deforestation one. It talked about lighter patches vs. darker forests, and hence a cooling effect. Well, that's true. But it's not in isolation. The real point behind the deforestation argument is in reference to greenhouse gases, and I don't even think they used this. Trees "breath" CO2 and give off oxygen, we learn that in what, 3rd grade? Concrete doesn't do this so well. So even if we emitted zero CO2, with deforestation and urbanization, atmospheric levels of CO2 would increase, as less is being removed. So this argument would say that it's still all about CO2 concentrations in the atmosphere, but that our focus shouldn't just be on the emissions end, but also on not taking away the things that absorb it!
