What caused the problem from 63 to 85?
Heat.
Part of the reason that folks still deny the changes going down is that they think it is all going to be an immediate thing you can measure over five years or something short like that. Global warming due to mankind has been going on for ages. We didn't start to pollute with the advent of the petrol engine, you know. We have been doing it with fossil fuels over centuries.
For some years when I lived in Glasgow, I can remember my mother bringing in grey washing - and we lived in a nice, leafy suburb, not in the city. As an apprentice, I can remember cycling home from work and having to get off and push the bike because I literally could not see a yard ahead. That was in the fifties. Later on, when I had a car, I recall driving back from the city following the tramlines, and hoping I remembered which turned off where. They brought in clean air acts, and that stuff became history. Fog, yes, a different but related beast, but the industrial smog was gone.
Today, engineering industry gasses (and coal fires at home) have been replaced as pollutants by vastly more cars and aircraft than ever existed before, and we produce pollution that is largely invisible to the naked eye if not to the lungs. Population growth has caused much more agriculture-based pollution than ever before.
It does not follow - never did - that every year would follow the exact pattern of the one before it; we go up and down, high and low, but the thing is, there is also an overall pattern to be considered, and that's what should get us thinking seriously. There's no denying that natural events like explodoing volcanoes and meteorite hits also caused vast climate changes in history; natural events indeed, but nowhere does it follow that man doing his best to stop his own pollution from getting worse is not going to help us survive - if only a little longer.
I think that's the whole point of what we are trying to do: stall the beginning of the end.