>> Finally, there is a new player in the climate game: human-emitted greenhouse gases. >>

There is another more sinister player, also delivered by human activity that started around the Industrial revolution.
Just the right timing, eh.

This player multiplies with industrial activity and much more rapidly in wartime, and there has been a lot of that.  
Carbon Dioxide is natural, it has been on this planet since the beginning, it has been in far higher concentrations with no deleterious effects.

But a micro layer of petroleum oil all over the seas of the world has never been tested before.
Oh on dams etc it has and it inhibits the evaporation of water.... it reduces cloud cover which leads to global warming.... until it brings global cooling and severe drought and ....

It could be that the warming in the middle ages is the baseline for our climate, we should have a more pleasant climate
then came our excretions...and the climate has been oscillation ever since, with wider and wider swings.

What is happening is not just a straight line effect, we are dealing with a swinging equilibrium.

OIL, you can see why this topic is never brought up, and why client scientists murky the waters.

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