Hmmm, "any casual reasonable observer" - that would be a scientist perhaps, and "casual reasonable observation" would be "science"?
Of course the data would be different with 60-70 years of improved collection techniques, analysis tools, and theoretical knowledge about the climate.
But this whole debate is pretty much a smokescreen. Sure, there are definitely error bars around temperature records of the past and estimates for the future. But one thing I have never seen be in question is the sheer amount of CO2 we have put into the atmosphere: https://www.climate.gov/news-features/understanding-climate/... .
The atmosphere now contains 50% more CO2 than pre-industrial times. The oceans are now 30% more acidic. These are gargantuan amounts. Sure, the global climate is incredibly complex, and how the climate reacts in different places in the world (e.g. ocean currents, ice cover, sea levels, temperatures, atmospheric humidity, storm intensity, etc.) is the hard work of some very smart people in climate science. But it's preposterous to me that we think we could raise the main global greenhouse gas by 50% and increase ocean acidity by 30% and not see some major impacts.
So while I think it's important to "worry about the details", only if done in good faith. Nitpicking around whether temperatures have rising 1.1 vs. 1.2 degrees, and using that as "evidence" that global warming isn't a problem or isn't worth doing something about, is what is so ridiculous in the face of avalanches of other data that we are seriously affecting the global climate.