Unfortunately, like "better safe than sorry", this just isn't true beyond feel-good virtue signalling. When you're dealing with nature and the environment it all comes down to assimilative capacity; under it and we're fine, over and we're screwed. No matter how many Denmarks make dramatic changes it means nothing without movement by the biggest emitters like China and the US.
Heck, the US might see what it did to Denmark and start its own version to compete and make "green" money. Being dismissive of good faith effort doesn't take us anywhere.
If everyone only points to each other and a "bigger real problem" you can hand wave everything away.
Meanwhile in the US...
https://www.washingtonpost.com/world/2018/10/11/few-countrie...
Oh, only two insignificant countries are meeting their treaty obligations.
How do you propose magically fixing everything at once without making any steps along the way?