verslagen1 wrote on 08/08/17 at 07:35:44:Long before co2 became an issue, this guy said we're about midway between ice ages, so naturally we are going to get as hot as it's going to get. Your rise and fall of civilization seems to correspond with a favorable climates and the Milankovitch Cycles support changing climate in various locals.
We are but a pimple on this earth compared to what the sun can do.
My son said rising co2 levels are not the cause of global warming, but an indicator of. And don't forget 9/11, a week w/out vapor trails being laid around the world and it got hotter.
Natural climate change being true does not make man-made climate change false. And the Milankovitch Cycle is one of many factors. Plus it's a 10,000 year cycle, so it's applicable in some examples but not all... But it doesn't even apply because the reality of man-made climate change is not dependent on this cycle.
I'm not sure what you mean by saying we're a pimple compared to the sun. The whole point of reducing CO2 emissions is that a CO2-rich atmosphere traps more of the sun's energy. Think of our solar system like temperate spring day. Venus is wearing a nice thick parka of CO2 which makes it uninhabitable and sweaty energy from the sun gets in, but it doesn't easily get out... Kind of like me on my bike lately... Earth is mostly Nitrogen (73%ish), but we're still wearing comfortable layer or two.
Mankind isn't some all-powerful god, changing the cosmos against the all-powerful sun... But we are putting on a proverbial jacket, and it's going to get pretty uncomfortable when we have to help dad dig postholes later.
Contrails have been known to mildly alter weather patterns for about as long as planes have be able to reach the heights and speeds needed to flash-crystalize vapor. The three days after 9/11 when most US flights were grounded added some interesting data, but it's not dramatic and it doesn't make things hotter.
Contrails are shown to act similarly to actual clouds, where they close the difference between the hottest and coldest temperatures of an affected region... They reflect heat back at the ground (keep energy in) and reflect light back up at the sun (Keep new energy from being added). But it's a pretty mild effect and isn't really effecting things on a macro level.