CANBERRA, Australia—After almost a decade of heated political debate, Australia has become the world's first developed nation to repeal carbon laws that put a price on greenhouse-gas emissions.

In a vote that could highlight the difficulty in implementing additional measures to reduce carbon emissions ahead of global climate talks next year in Paris, Australia's Senate on Thursday voted 39-32 to repeal a politically divisive carbon emissions price that contributed to the fall from power of three Australian leaders since it...