COPENHAGEN – A U.S.-based global alliance to speed up efforts to tackle climate change, whose participants inaugural host country Denmark said represented more than a quarter of the world economy, will be launched on Wednesday.

Formalized two days after the United States confirmed its plans to quit the landmark Paris climate agreement of 2015, the initiative aims to create a forum for sharing knowledge and technology between governments, businesses and community leaders.

Those joining the New York launch and supporting Partnering for Green Growth and the Global Goals 2030 (P4G) include China, Indonesia and the C40 network, the office of Danish Prime Minister Lars Lokke Rasmussen said in a statement.

C40 connects more than 90 cities representing a quarter of the global economy, of which 12 are American.

“We have all realised that the (U.S.) president is not, after all, almighty. And we see a long list of states – like California and Texas – wanting to do something different on the climate issue,” Rasmussen told newspaper Berlingske.

Donald Trump’s top economic adviser told a U.N. meeting on Monday that he stood by his intention to abandon the Paris pact unless there was a renegotiation more favorable to the United States, a step for which other countries have little appetite.

P4G will have its international base in Washington D.C. from January, and hold its first summit in Copenhagen next November.