I'm not confident that scientists can at a minimum measure the temperature and determine if it's getting hotter on average...without intentionally introducting their own bias into their analysis.

Hotter or coler is a realative assessment (i.e. hotter or colder than what?)

The timeframe and comparative scope that is chosen can alter the final result...

Are we "hotter than" the last ice age? (I'd argue yes)
Are we "hotter than" yesterday? (For where I live, the answer is no)

So compared to the last ice age we have global warming...
Compared to yesterday we have global cooling...

Statistics are relative--and it's quite simple to manipulate any statistical result to suit your own purposes and sway opinions....