The title of the study is "Arctic warming four times faster than rest of the earth". Warming is not the same as melting, but melting is more clickbaity. In accepted climate models, it was previously assumed that Arctic is warming twice as fast as rest of the earth, but this shows those models were insufficient.

Another thing is that, this was conducted around Arctic circle. The rate of warming varies around different regions. Svalbard is warming up 7 times as fast (1.25 C per decade) compared to rest of the earth

It's a process with stages: melting (where ice is available) -> evaporating (if there is water) -> burning (of the dry forests when there is not enough water) -> desertification (of the barren land when water, forests and other vegetation are gone). But yeah, Arizona is mostly already in the final stage, and I guess you can't really compare the speed across all stages anyway.