The ol’ Merkel smirkel. Image by א, Wikimedia CommonsBERLIN — German Chancellor Angela Merkel said on Tuesday she would only attend the Copenhagen climate conference in December if the U.S., China, and India first make clear their negotiating positions.

“The European Union has developed clear and unambiguous negotiating positions. We now want contributions from the U.S. and from countries like China and India,” Merkel said in the first major policy speech of her second term.

“I will make a special personal effort to achieve this. And of course if it is successful, yes, I will go to Copenhagen,” Merkel said.

She added:

A failure of the world climate conference in Copenhagen in December would set international environmental efforts back by years. We cannot afford this.

A substantial political agreement is indispensable in order to create conditions for a binding international protocol for after 2013. Time is pressing.

The aim of the Copenhagen summit is to hammer out an accord for 2013 onwards that will include emission cuts and aid to help poorer countries develop low-carbon economies and deal with the ravages of climate change.

Forty heads of state or government, including British Prime Minister Gordon Brown and French President Nicolas Sarkozy, have indicated they will attend the climax of the Dec. 7-18 talks in the Danish capital.

But with signs growing that the get-together will fall short of achieving a binding, historic pact, it is unclear whether other leaders, most notably President Obama, will show up.

Washington has been reluctant to declare its hand while a climate bill inches through Congress.

An E.U. summit in late October agreed that developing nations will need 100 billion euros ($146 billion) per year by 2020 to tackle climate change, but leaders from the 27 nation bloc failed to nail down how much it would give.