Climate change and Milankovitch cycles

[muon2]

I'll defer your main question to a qualified scientist, but I feel the need to point out that scientists were predicting temperature rises due to CO2 in the 1800s, and the idea that "scientists used to say we were headed to an ice age!!!11" is a typical conservative #fakenews myth/lie.

Also 95% is a huge overestimate of the northern hemisphere population.

In the late 60's and early 70's I was young and reading a lot of science on my way towards a career. I can confirm that the majority of material I read from reputable sources feared a cooling of the planet towards a new ice age. There were relatively few writers talking about the greenhouse effect.

[muon2]

I'll defer your main question to a qualified scientist, but I feel the need to point out that scientists were predicting temperature rises due to CO2 in the 1800s, and the idea that "scientists used to say we were headed to an ice age!!!11" is a typical conservative #fakenews myth/lie.

Also 95% is a huge overestimate of the northern hemisphere population.

In the late 60's and early 70's I was young and reading a lot of science on my way towards a career. I can confirm that the majority of material I read from reputable sources feared a cooling of the planet towards a new ice age. There were relatively few writers talking about the greenhouse effect.

I'm not calling you a liar, but you are either misremembering or were reading sources like Newsweek instead of academic journals:

https://www.skepticalscience.com/ice-age-predictions-in-1970s.htm

I was in 7th-8th grade in 1970, and I didn't have access to scientific journals. I did read what was available at the public library and that tended to be works of popular science and articles in general news magazines. Environmental changes due to smog were an important topic in the news in the 60's, and air quality in LA was described like Beijing is today. As your link notes, scientists studying northern hemisphere cities had identified aerosol smog as a cooling factor and had observed a cooling trend based on that data set. The idea of particulates leading towards a colder planet was heightened in the press during that time of the Cold War with discussions of a "nuclear winter" resulting from dust kicked up by a WWIII.

[muon2]

One of the other issues driving coverage in the 1960's was the desire to make more of the earth suitable for agriculture and development. That meant that warming was not as bad as an outcome as cooling would be. Consider this section from the last chapter of the 1965 book Weather, part of the Life magazine Science Library, written by the associate director of the National Center for Atmospheric Research.

He does comment on the potential impact of carbon-induced global warming:

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Yet in the very next paragraph he describes a number of far-fetched ideas that would have some of the same warming effect, but casts them in a more positive light:

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This is the type of popular science written by professionals that drove thinking back then. These ideas would cause ice cap melting, just like excess carbon dioxide, but they are presented in a more positive light. It's that type of writing that caused the public to react more to potential ice ages than to global warming.