Denmark's premier sent invitations Thursday asking 191 world leaders to attend next month's U.N. climate conference in Copenhagen, saying their presence was "pivotal" to its success.
Danish Prime Minister Lars Loekke Rasmussen, will chair the Dec. 7-18 talks aimed at reaching a new global pact to curb emissions of greenhouse gases blamed for global warming.
"Your personal attendance is a pivotal contribution to a successful outcome," Loekke Rasmussen said in the letter to world leaders, dispatched through diplomatic channels.
At least 40 leaders have said they plan to attend the conference, which follows two years of tough U.N.-led negotiations to draft a climate change agreement to replace the 1997 Kyoto Protocol, which expires in 2012.
They include British Prime Minister Gordon Brown, French President Nicolas Sarkozy and Dutch Prime Minister Jan Peter Balkenende.
President Barack Obama has said he may come if his presence would help clinch a deal. U.S. climate delegate Jane Lubchenco said Thursday in Copenhagen that Obama believes an agreement next month is "critically important" and he is "actively considering" attending the meeting.
High-level meetings of politicians at Copenhagen are expected to start Dec. 16, with heads of state and government joining in the following two days.
Loekke Rasmussen invited them to a gala dinner hosted by Denmark's Queen Margrethe "followed by meetings and activities" on Dec. 18 _ the final day of the conference.
"Many countries have already announced or passed significant legislation to reduce emission levels and adapt to the negative effects of climate change," the Danish leader said in the invitation.
President Luiz Inacio Lula da Silva of Brazil has indicated he might come to the conference, and a spokesman for German Chancellor Angela Merkel said she is keeping the date open.
U.N. Secretary-General Ban Ki-moon strongly encouraged all heads of state and government to attend the summit.
"The secretary-general believes it is essential to maintain political momentum at the highest level and from all sectors of society, and is optimistic than an ambitious, fair and effective climate deal can be reached at Copenhagen," U.N. spokeswoman Michele Montas said in a statement issued at U.N. headquarters in New York.
Meanwhile, the European Union _ which has said it hopes to lead global climate policy _ said it will meet or exceed its target of cutting greenhouse gas emissions by 8 percent below 1990 levels by the year 2012.
Europe "can be relied on to deliver" its promised reductions, EU Environment Commissioner Stavros Dimas said in Brussels. By 2020, the 27-member EU has vowed to slash emissions by 20 percent, and said it would step that up to 30 percent if the United States, China and other nations also pledge ambitious cuts in carbon dioxide emissions.
Associated Press Writer Edith M. Lederer in New York contributed to this report.