Let's be clear, we are talking specifically about the incorrect ice age scare, you mentioned, of about 1965 to 1980. So any talk of climate denialists, or "greenhouse denialists," is not at all relevant, and sounds more like a personal grudge than science.

During the ice age scare, there was about a decade of minimal solar activity. Coupled with pretty mild weather patterns over the same period of time, this lead to some lower temperatures that sparked the fear.

Variation in the solar radiation on earth is by around 0.1% from solar minimum to solar maximum.

Well, that isn't exactly true....

The solar constant is measured from space and is dictating that the variance of solar radiation to the Earth, before penetrating the atmosphere, doesn't seem to vary much. This is mostly a recent historical measurement, with satellites, of the variation due to Milankovitch cycles, the many different movements of Earth and how that impacts climate.

Yet, there are many wavelengths of solar radiation which impact our Earth, some wavelengths are affected by greenhouse gasses more so than others, some not at all, some are reflected by certain atmospheric particles, some are not.

We like to measure this solar irradiation in very many different ways., which the Solar Constant is just a measurement of Flux, before the atmosphere.

While the scale is very large and we don't can't easily find recent scaled charts of variations in various solar activity and irradiance energy, we can even see them in the large scale chart. Despite scaled by 200 years, the tick mark at 100 years you can use for a reference and you'll see how all charted aspects dipped about the same time, including the global temperature, which you could guess by that 100 year before tick, to be generally around 1970.

https://upload.wikimedia.org/wikipedia/commons/7/7e/Milankovitch_Variations.png

There is whole papers and books on this topic you can read. Actually, a SaidIt user pointed me to one which enlightened me, although I can't find the link or name at the moment. I don't think it was uncommon, something like 'the non-scientific consensus of' the ice age scare or something. It was a good read.

It seems the newspapers mostly drove the scare, but winding the end of the scare, came the emerging scientific concepts of green house gasses. These followed shortly after the flawed CO2 study of the 1970's, that measured the warm up from CO2 as this ice age scare ended.

Of course, it is pretty easy to assume from the historical records, that we are becoming due for an ice age after this warming period completes. It will, of coursed, be anytime between now and 10's of thousands of years, so I would hold my breath.

I expect a nice big polar vortex between this winter and next, probably a little worse than 2000, mostly due to the extreme El Nino we've had. That should be fun.