To say that you've seen that is like hearing somebody claim to have seen angels and spirits.
What you have seen is weather.
To the extent that there has been climate change, bearing in mind that the climate is dynamic and always has been, how do you know what it would look like right now if there hadn't been any human society? You cannot know what it would look like and nor can anybody else. You can guess or hypothesise, you can try to model it. That is all.
And this brings us back to my point, it isn't about acting or burying one's head. Those are extremes. How much action should be taken on the precautionary principle? There is a massive scale here. Do you want to dramatically reduce the human population? If so, will you be volunteering? Do you want all cars and heating systems to be banned? Do you want green taxes? What do you want to be done to address a problem you have admitted is not certain? Also, what do you intend to do about China, India and the other countries who don't give a damn about it and are building fleets of coal powered plants on a monthly basis? In case it has escaped your attention, we now have very little in the way of industry or a military and have massive debts, so our ability to force action is pretty limited. Same applies to the rest of the Western countries, bar the US which is also declining relative to the other major world bloc.
I'm not saying you are wrong, but asking what it is you think should be done and when will our sacrifices be enough to satisfy your interpretation of the precautionary principle?