UNITED NATIONS, April 23 (Xinhua) -- UN Special Envoy for Climate Action Michael Bloomberg has announced a contribution of 4.5 million U.S. dollars to the UN Climate Change Secretariat, the UNFCCC, a press release said Monday.

The billionaire philanthropist and former mayor of New York City, pledged last June to make up the Secretariat's funding shortfall, caused by U.S. President Donald Trump's announced withdrawal from the historic 2015 Paris Agreement on climate change.

The United Nations Framework Convention on Climate Change (UNFCCC) said that with many contributions from signatories to the agreement still outstanding and "a decline in voluntary contributions," the funding was arriving at "a critical time," according to the press release.

The contribution will go towards general operations, including assisting countries to meet targets for cutting greenhouse gas emissions in line with the accord, agreed by 193 states in the French capital.

In late March, the U.S. Congress announced that it was cutting funding for this year to the UNFCCC by 4.5 million dollars, from 7.5 million dollars down to 3 million dollars.

Bloomberg made the announcement of his contribution on the CBS television program "Face the Nation," saying that "America made a commitment and as an American, if the government's not going to do it, we all have a responsibility."

UN Secretary-General Antonio Guterres tweeted that he was "very grateful to Michael Bloomberg, not only for his generous support to the United Nations, but also for his global leadership on climate action."