The most important thing for you to know about the upcoming United Nations Climate Summit is what it isn’t.

The meeting, to be held at the U.N.’s New York headquarters this Tuesday, Sept. 23, will be the first time heads of state have gathered to discuss global warming since the 2009 U.N. Climate Change Conference in Copenhagen. So casual observers might think this is the opening round of negotiations on an emission-reduction agreement that will hopefully be completed at the U.N. Climate Change Conference in Paris in December 2015. But it isn’t.

This Climate Summit should be viewed as distinct from the treaty negotiations that are intended to wrap up late next year. “It’s not designed to be a pre-negotiation for Paris,” cautions Nigel Purvis, who directed U.S. environmental diplomacy in the Bill Clinton and George W. Bush administrations and now runs the Climate Advisers consultancy.