Okay, what about these "adjustments"? Click here and scroll down to the third (animated) graph. These are the (too-often applied) "adjustments" that people are talking about. Frankly, some of these are phony as discussed in the article. There is no reason (in this example) to believe 1936 was cooler than it was measured at the time.
Some adjustments are necessary and some are nonsense. There have been calls for criminal investigations into record tampering in Australia. The Hadley Center in Great Britain (correctly) puts error bars (0.1°C) on its yearly world temperature chart. This is the way these values should be expressed (see below). From where I sit, the honest climate scientists should be condemning record tampering in the loudest manner possible but, for reasons understood only by them, they sit silent.
There is zero doubt in my mind world temperatures are warmer today than they were 40 years ago. In south central Kansas, below zero temperatures are becoming rare while the number of ≥100°F temperatures are staying about the same. It appears southern Kansas' climate has become milder with, in general, more consistent rainfall and less extreme temperatures.
Do I believe the amount of warming may be exaggerated, in part because of these "adjustments"? Yes, that is possible. That stated, global warming is a problem. Not a major problem, but a problem that will need to be dealt with.