What is climate denial? Please define. I hope this is a reference to the debate regarding the magnitude of the climate sensitivity parameter. If not, then what is it? No one of any consequence (least of all, someone like Richard Lindzen) denies that there is such a parameter and that it is central to the climate question. So what value would you go for and why? I guess a climate denialist would say it has a value of zero (denies science as we understand climate at present) but we can conclude that Arrhenius (at '5') went too high. https://en.wikipedia.org/wiki/Climate_sensitivity So it lies somewhere in between.