The Paris climate deal aims to prevent the Earth from heating up by 2C since the start of the industrial age.

The UN chief on Saturday urged the US to re-engage with the 2015 Paris climate agreement even after America submitted its formal communication indicating its intention to withdraw from the historic pact as soon as possible.

UN Secretary-General Antonio Guterres has received a notification from the U.S. expressing the country’s intention to withdraw from the Paris Agreement on climate change, his spokesman said.

The notification received on Friday was communicated by U.S. Permanent Representative to the UN Nikki Haley.

“The Secretary-General received, in his capacity as Depositary of the Paris Agreement, a communication from the Permanent Representative of the US expressing the intention of the US to exercise its right to withdraw from the Paris Agreement, as soon as it is eligible to do so under the Agreement, unless it identifies suitable terms for reengagement,” UN spokesman Stephane Dujarric said.

The Paris climate deal aims to prevent the Earth from heating up by 2C since the start of the industrial age.

The spokesperson added that the secretary-general “welcomes any effort to reengage in the Paris Agreement by the United States”.

The notification came two months after President Donald Trump announced his intention to leave the accord.

Under article 28 of the Paris Agreement, a party may withdraw at any time after three years from the date on which the agreement has entered into force for that party, and such withdrawal takes effect upon expiry of one year from the date of receipt by the depositary of the notification of withdrawal.

The US accepted the Paris Agreement on September 3, 2016 and the agreement entered into force for the US on November 4, 2016. This means that the US must stay in the pact until at least 2019.

The note referred to the June statement by the secretary-general in which he had said that the decision by the United States to withdraw from the Paris Agreement is a “major disappointment” for global efforts to reduce greenhouse gas emissions and promote global security.

“It is crucial that the United States remains a leader on climate and sustainable development. Climate change is impacting now,” Dujarric said, adding that the UN Chief looks forward to engaging with the American government and all other actors in the United States and around the world to build the sustainable future for our children and future generations.