Sadly, Prime Minister Shinzo Abe has just flubbed a wonderful opportunity to show his green credentials for the benefit of Japan and the world. Asked about the Paris agreement on climate change, he replied with a boilerplate statement that Japan will "keep playing a leading role in the international community" in the battle against global warming. But he also promised that Japan won't sacrifice growth in fighting against climate change.

The truth is that Japan's role in reaching the Paris agreement was distinctly underwhelming; commitments it has made to reduce greenhouse gas emissions — by 26 percent below 2013 levels by 2030 — are less than it promised under the Kyoto Protocol of 1997. Worst of all, there is no sign that Tokyo plans to take the lead in making sure the Paris deal actually works.

World leaders joined hands jubilantly and sang their own praises over the weekend, having finally reached an agreement to curb greenhouse gas emissions and limit the Earth's temperature rises to 2 degrees Celsius above preindustrial levels. They also agreed to work together to restrain the rise to 1.5 degrees.