Taro Aso, Japan’s prime minister, on Wednesday unveiled the country’s long-awaited medium term target for action against global warming, saying the world’s second largest economy would cut emissions of greenhouse gases by 15 per cent from 2005 levels by 2020.

However, climate change activists immediately denounced the target – which amounts to only an 8 per cent reduction compared with Japan’s 1990 emissions – as a disappointing concession to industry that could cost Tokyo any chance of playing a leadership role in international climate change negotiations.