Absolutely right. Pretending to take the temperature of the Earth with so few measurement points is ridiculously stupid.
Climatic change can be measured in caves. The temperature within a cave is in fact the average 24/7/365 temperature for that location. Locally that temp is said to be 55° F.
If there is in fact significant warming, cave temperatures will rise.
I looked for a plot of Mammoth cave temps over time but could not find one