The United Nations climate summit opened in Copenhagen, Denmark, on Dec. 15 with strong calls for world leaders to reach a “fair ambitious and comprehensive” deal.

Speaking at the ceremony, UN Secretary General Ban Ki-moon called on delegates to seal the deal, that reduces greenhouse-gas emissions, protects the most vulnerable, and ushers in a new era of clean development and green growth for all.

According to the UN chief, with the attendance of more than 130 world leaders plus strong support from all social strata from businessmen, civil organisations, religious organistions and the youth, this is a defining moment in history in response to climate change.

To translate the target into reality, developed countries should have their stronger medium targets for reductions in emissions while developing nations take actions to keep gas emission under normal level, according to Ban.

The climate summit opened amidst large gaps on targets for gas emission cut and developed countries’ responsibilities in helping poor nations to climate change resilience./.