Re: Science provides facts, you decide.
"The IPCC is tens of thousands of scientists, not politicians."
This is manifestly untrue. IPCC chairman Rajendra Pachauri claims 2,500. Dr Mike Hulme
: "Claims such as '2,500 of the world's leading scientists have reached a consensus that human activities are having a significant influence on the climate' are disingenuous ... The actual number of scientists who backed that claim was only a few dozen."
"it is no longer rational to dispute the greenhouse effect (as any gardener would tell you) or that it is the direct and indirect consequences of human activity that is the overwhelming contributor to the accumulation of CO2 and CH4 in the atmosphere."
You conflate two very different processes here. The greenhouse in the garden works by inhibiting convection. "Carbon pollution" does not
"When Jerry Pournelle wrote about it, the science was less clear cut."
Warmists regularly invoke Svante Arrhenius' (19 February 1859 – 2 October 1927) and his erroneous explanation of how greenhouses work in support of their case. I make no doubt that none of them have ever read what Arrhenius wrote:
"We often hear lamentations that the coal stored up in the earth is wasted by the present generation without any thought of the future, and we are terrified by the awful destruction of life and property which has followed the volcanic eruptions of our days. We may find a kind of consolation in the consideration that here, as in every other case, there is good mixed with the evil. By the influence of the increasing percentage of carbonic acid in the atmosphere, we may hope to enjoy ages with more equable and better climates, especially as regards the colder regions of the earth, ages when the earth will bring forth much more abundant crops than at present, for the benefit of rapidly propagating mankind."
Worlds in the making: the evolution of the universe 1908, p63.