Random thoughts:
At 1 time the Earth was warm. Climate changed and the Earth became covered with ice. What unnatural event caused that?
Several natural things, but was initially triggered by Milankovitch Cycles, which are small wobbles in Earth's orbital path, that then set off a cascading series of positive feedbacks whose net effect lowered temperatures.
At 1 time the Earth was covered in ice. Climate changed and the Earth became arm. What unnatural event caused that?
Actually, the Earth has been covered in ice many times in the relatively recent geologic past. A very very long time ago (long before dinosaurs and such), we came perilously close to the "Iceball Earth" scenario, where a threshold of reflectance from ice fields covering a large portion of the globe would have resulted in a permanent planetary freeze. Luckily, this didn't occur. In the recent past, again Milankovitch Cycles played the dominant role.
Global warming would cause increased evaporation which would cause increased rain which has a cooling effect.
Global warming causes increased temperatures as well which increase the specific humidity required to reach 100 % saturation, which is necessary for rain. Thus, while net evaporation increases, cloud formation and precipitation become increasingly regionalized, leading to areas of drought. Areas of drought get lower environmental humidity and decreased reflectance from clouds, leading to spreading aridity and increased surface temps, as water is not available to evaporate and store energy as latent heat. Your premise isn't really accurate, at least not fully.
History teaches of the industrial revolution; skys saturated in pollution, cities under a 24x7 dark haze. In my lifetime I have seen cities covered in smog; industrial smoke stacks belching pollutants unfettered into the sky. The air is cleaner now than it has been in the past.
This is true to an extent. There are less sulphates and smog particles today than in the recent past in the US and Europe. However, sulphates have a cooling effect anyway, and the greenhouse gasses such as CO2 are not visible. Alas, the US and Europe are only one small part of the world. China is belching out pollutants like there's no tomorrow, India is pretty lax on emission rules out of poverty, and Africa is basically unregulated. That is most of the world's population, and they are rapidly industrializing.
I am less concerned about what my car puts into the atmosphere and more concerned about the deforestation of the rain forest. Q: Why do scientists spend their time shaking down industrialized nations over rain forest countries? A: They have the money.
The reason why more focus is put on industrialized nations is not as cynical as you think. How do you tell a Brazilian farmer that he isn't allowed to burn another plot of rain forest after his old plot has been exhausted of nutrients in only a couple of years, and that he and his family must starve? How do you tell impoverished people barely scraping by to stop scraping? Also, where can better techniques and technology be implemented- a third world hell hole or an industrialized society with a surplus of resources?