COPENHAGEN — Louise Purup Nohr’s morning routine is like something out of a sustainable future.

When she hustles her kids into the bathroom, what flushes down the toilet will later turn into the natural gas that warms breakfast on the stove. The eggs come from the chickens in the backyard. The coffee machine’s gurgling is powered by electricity generated from the wind. The water that washes the dishes is heated by sustainable sawdust pellets. The recycling gets shunted in eight directions, so that little ends up in the dump. And the commute — first to school, then to work — is on a cargo bike that bumps across Copenhagen’s extensive bike-lane network.

Amid mounting global concern about climate change, Denmark has turned into a buzzing hive of green experimentation, with efforts underway inside homes, across cities and on a national scale.