In his first birthday address since ascending the chrysanthemum throne, Emperor Naruhito pledged to stand by the people of Japan in responding to intensifying environmental and social challenges ranging from climate change to the novel coronavirus outbreak.

"In this rapidly changing society, I am contemplating measures in our official duties that would be complementary with such societal changes," said the emperor, who turns 60 on Sunday, during a Friday news conference held in commemoration of his birthday.

"I believe the imperial family bears a share of the responsibility" to address such challenges, he told reporters at his residence near the Imperial Palace.