The classic mistake they ALL make is that they say that because the temp changed before, that the current climate change is just natural.Fake news!
The climate has always changed!
Had this discussion with an friend who was banging on about how it was all bullshit and that he was told in school years ago that we were supposed to be getting colder and having an ice-age. He did a double take when I confirmed that we are supposed to be getting colder, but not necessarily ice-age levels. Then I had to explain about the long term wobble (41 000 yrs) in earths orbit around the sun known as Milankovitch cycles. According to the data we are in a cooling phase, but we have also known since Arrhenius' paper in 1896 that man-made co2 emissions would have a warming effect. So, that means that currently our man made warming is actually countering the natural cooling cycle. Then showed him long term time-framed (course of human history so, ~200 000 years of ice-core data) hockey stick graph which shows the natural cycles, then in the last 200 years how the temp rise has totally destroyed the natural time component.
Finally, he is about my age, so asked him to remember when we actually had consistent cold winters. He had his kids out for Halloween in summer clothes and I had to remind him about trick or treating in the snow was not out of the ordinary when we were kids.
Not sure If I totally got through to him, but I at least made him think.
The correlations that have been made and confirmed show that it's the RATE OF CHANGE in the time period that shows the change. It's not how much, or that it's gotten hot/cold before...it's the RATE OF CHANGE since CO2 started going into the atmosphere.
You can usually stump those idiots by just getting them to tell you what they think the theory is here, when they don't even know what the theory is, they are totally unqualified to have an opinion on it IMO.