Scientists say that the Arctic ice cap is melting faster than ever
US President George W Bush will not be present, hosting instead a meeting of 16 "major emitter" countries in Washington on Thursday and Friday.
However, the attendance of 150 countries and 80 heads of state makes Monday's meeting the most high-level UN gathering on climate change.
Mr Bush, who does not support binding emission targets, will not take part in the formal discussions but will be joining Mr Ban and other key leaders for dinner.
-source BBC News website
“The most high-level UN gathering on climate change” and Mr. Bush is not interested in the discussions but “will be joining Mr. Ban ki Moon (UN Secretary General) for Dinner”