What dates would you use to get an average? Start from the beginning of the planet?
You may have missed my points.
To answer your facetious question, no. From the beginning of the planet would be even harder than from 1850.
I would begin at a time when modern, high-sensitivity gauges were installed fairly evenly around the world — preferably in rural areas, away from all the artificially hot surfaces. That way you would be comparing apples with apples. That is a must if you’re doing science.
But the alarmists are doing agenda-driven speculation, not real science. So it doesn’t matter to them how iffy their measurements from the past might be.
My second question is one the alarmists never answer: what average temperature of the surface of the earth would be acceptable to their sensibilities?