I should admit that my specialty is chemistry and not environmental science so it is hard to make arguments here. Just a few comments: - it should be proven that these other effects are the causes not correlations. - what invasive diseases you are talking about? smallpox or syphilis? - drought was always a thing, e.g. great famine of 1921 in USSR was caused by it. That was way before modern levels of global warming. - There were at least 5 ice ages. Are the humans responsible for their endings?

I am convinced that climate is changing — just not fully convinced what is the human role in it.