New targets to eliminate the gases driving climate change from Wales’ economy and way of life are to become law.
The Welsh Government said “business as usual” was no longer an option.
Changing weather patterns are already “wreaking havoc” and acting now is “the right thing to do for our children and grandchildren”, it says.
The move brings Wales into line with the UK push for “net zero emissions” by 2050.
However, environment minister Lesley Griffiths said she wanted to “get there sooner”.
It will mean huge upheaval – from replacing hundreds of thousands of gas boilers in people’s homes, to potentially finding new ways of making steel at Port Talbot without burning coal.