It was a record number of the signatories to a new international treaty, which was adopted in Paris in December 2015.
France's president Francois Hollande was the first to sign the document. He said the agreement in Paris was an "emotional moment, rare in the lives of politicians and leaders," according to BBC News.
He added: "We need to go further than the pledges made there."
Permanent Representative of Ukraine to the United Nations Volodymyr Yelchenko signed the treaty on behalf of Ukraine.
Історичний момент – #Україна підписала Паризьку угоду про боротьбу зі зміною клімату #ParisAgreement@YelchenkoUNpic.twitter.com/kdnRbjjinR
— UKR Mission to UN (@UKRinUN) April 22, 2016
About 15 nations, mainly small island states, had already ratified the agreement. But dozens of other countries were required to take this second step before the pact came into force, BBC News said.
UN Secretary-General Ban Ki-moon said: "Paris will shape the lives of all future generations a profound way – it is their future that is at stake."
Speaking at the opening ceremony, he said the planet was experiencing record temperatures: "We are in a race against time I urge all countries to join the agreement at the national level."
"Today we are signing a new covenant for the future," he added.
The official ceremony of signing the Paris climate agreement at the UN Headquarters in New York
UNIAN memo. At the Paris climate conference (COP21) in December 2015, some 195 countries adopted the first-ever universal, legally binding global climate deal.
The governments agreed to come together every 5 years to set more ambitious targets as required by science; report to each other and the public on how well they are doing to implement their targets; track progress towards the long-term goal through a robust transparency and accountability system.
The agreement sets out a global action plan to put the world on track to avoid dangerous climate change by limiting global warming to well below 2°C.
The agreement will enter into force after 55 countries that account for at least 55% of global emissions have deposited their instruments of ratification.
The agreement is due to enter into force in 2020.
