The part of the climate change argument I take most issue with isn't regarding measurement; the argument of "More carbon in air = we getting hotter" is a fine one.
I do, however find it very dishonest when the alarmism focuses on industrial output of carbon, as if turning first world production "off" would even remotely solve the issue. I could easily get on board with eventual full scale modernized nuclear for baseline power + renewables (hydro, solar, wind where applicable). So, that's all well and good for a developed country. If there was a political will (there isn't) for it, and an honest effort to remove all of the red tape around nuclear energy (there isn't), there's no reason it couldn't be made to happen within 5 years.
But then what to do with everyone else? You're never going to get Nigeria, or India, or Indonesia, or whichever other populous developing country of your choice to do anything meaningful to curb their emissions in the very short (as in now) timeframe given by our current day alarmists. Also, that is only focusing on the belief that our measurables are even correct. Does anyone actually know what each country produces, in reality? I would say no. I doubt very much that most countries in the world even know how many people they really have. The US doesn't even know how many we have, we just take a census, and estimate the rest.