More than 130 nations have pledged to sign the Paris climate change accord on Earth Day when the signing ceremony begins at United Nations headquarters in New York, the U.N. announced Friday.
The number of signatures would secure ratification of the global deal in one day, achieving a key objective of President Obama's final year in office.
Nations have one year to sign the accord, and it takes 55 signatures to ensure it goes into effect.
President Obama has been scrambling to get leaders to pledge to sign the deal by his side, with Chinese President Xi Jinping being the latest to do so last week.
Obama and Canadian Prime Minister Justin Trudeau made pledging to sign the Paris accord a key component of a state visit last month to the White House.
The Paris deal ensures that countries will reduce their greenhouse gas emissions by investing in renewable energy and other innovations, while being able to prove they have reduced emissions through strict accounting requirements.
The goal is to ensure the Earth's temperature does not exceed 2 degrees Celsius over the next two decades.
Many scientists blame greenhouse gas emissions for raising the Earth's temperature, resulting in sea-level rise, glacier melting and flooding.