> How

Science!

https://en.wikipedia.org/wiki/Temperature_record_of_the_past...

There's an emphasis on the word "likely" in that article, so it's speculation at best.

It's not words: science has much more exact way to estimate the confidence in any scientific result -- numerically! The estimates are valid and good. It's certainly not "speculation" like you now "speculate" with your doubt, but it's a scientific estimate, guided by the scientific processes. To dispute them, you'd have to raise to that level, be educated enough and able to understand the work already done, not speak empty words of doubt.

Your appeal to authority isn't convincing.

I'm definitely not appealing to authority. I'm claimng that nobody should take you seriously when you don't understand the topic and moreover even show that you don't want to learn.

If you weren't appealing to authority you could make your point without referring to an authority. But what you told me was that there is an authority who said something that I am not allowed to dispute without also becoming part of said authority. Hence my reaction: your appeal to authority isn't convincing. Feel free to use exactly the same arguments your authority would use, but just saying "because they said so" won't convince me.