Climate change is no longer a matter for scientific debate, but has become a question to be solved at the international political level, Secretary-General Ban Ki-moon's three new Special Envoys on the issue said today, pledging to use their experience from previous posts and their contacts with national leaders and other senior figures to galvanize more concerted environmental action. The three envoys � former Norwegian Prime Minister Gro Harlem Brundtland, former Republic of Korea Foreign Minister and General Assembly President Han Seung-soo and former Chilean President Ricardo Lagos Escobar � held a working luncheon today with Mr. Ban, who announced earlier this year that tackling climate change is one of his priorities as head of the UN.