Thirty-one countries formally joined the Paris Agreement on climate change on Wednesday, surpassing a major hurdle toward putting the landmark pact into force.

The agreement cannot go into effect until 55 countries accounting for at least 55 percent of global emissions have ratified or accepted it through their own domestic procedures.

"I am happy to declare that we have officially crossed one of the two thresholds required to bring the Paris Agreement into force," Ban said at the ceremony referring to the total of 60 countries that have so far done so.