Sure, temperatures have changed before. But the rate of change this time around is as much of a problem as the amount of change: https://xkcd.com/1732/
Please consider not getting your supporting evidence from a comic strip. As you can see by the full data set Randall Munroe truncated the time scale to fabricate his narrative. Here is the same data set he used except going back 800k years instead of 20k...
sintaxi|5 years ago
https://www.ncdc.noaa.gov/global-warming/temperature-change
thundergolfer|5 years ago
Looking at your linked 800k graph it’s impossible to see the effects of the 1800 AD to 2000 AD period, which is where all the interest is.
I think you’re confused about what Munroe is communicating in his comic.