In the two weeks since his inauguration as a Cabinet minister, young scion Shinjiro Koizumi has seen his populist rhetoric — one of his biggest political weapons in making him the darling of the public — increasingly turn into a liability, earning him criticism and ridicule on social media.

Koizumi, a son of former Prime Minister Junichiro Koizumi, has yet to make a critical slip of the tongue that would jeopardize his nascent career as the environment minister. But the past two weeks have seen the press and social media vet his speeches more stringently than before, treating the new minister to something of a baptism of fire.

Koizumi made headlines this past weekend when he made a diplomatic debut in New York at a United Nations-hosted climate summit. Speaking to reporters on the eve of the summit, the 38-year-old enthused in English how he thinks the fight against climate change should be made "sexy."