The U.N.'s fund for climate aid to developing countries says it now has enough cash to kick off projects before a key climate summit in Paris.

Green Climate Fund officials said a Japanese commitment Thursday of $1.5 billion pushed the fund's resources beyond the threshold at which they can start financing projects in developing countries.

U.N. officials had hoped to reach that milestone already by the end of April, well in advance of the Paris summit in December, but lacked signed agreements for funding from major donors including the U.S. and Japan.

The fund now has signed agreements for $5.47 billion out of the $10.2 billion that countries have said they will contribute.

The GCF aims to help developing countries limit their greenhouse gas emissions and adapt to climate change.