The Tokyo Metropolitan Government became an official member of the International Carbon Action Partnership (ICAP) on May 26, 2009, when Tokyo Governor Shintaro Ishihara signed ICAP's political declaration of principles and objectives. Tokyo says that by joining ICAP it aims to:

(1) actively take part in debate about the creation of a global carbon market and contribute to the launch of a nationwide cap-and-trade system;
(2) assimilate knowledge on operations of existing cap and trade systems around the world through working-level talks, in order to operate Tokyo's cap-and-trade system more effectively; and
(3) introduce Tokyo's cap-and-trade system to the world as a model to create a low carbon society in large cities.