How they knew what satellites can tell us today in 1880 is less clear.
AMEN! I believe the aggregated data collected in the satellite era. Lots of calibration and global coverage.
HOW can anyone with a straight face compare that to surface-only temperatures taken with calibrated? uncalibrated? mercury thermometers in a scattered patchwork around the earth? And we are still only within a degree or so of those measurements!
I wonder what would happen if we took our current measurements from only those same 1880 locations and did the analysis. I wonder how it would all turn out.
Between high school and college, I took 6 years of chemistry. When doing labs, I was never allowed to mix significant digits! But they have no problem declaring a win over a 0.01 degree difference.
Makes me want to pound my head.