As many as 170 countries are expected to sign the Paris Agreement on climate change tomorrow in a symbolic triumph for a landmark deal that once seemed unlikely but now appears on track to enter into force years ahead of schedule.
UN officials say the signing ceremony tomorrow will set a record for international diplomacy: Never before have so many countries inked an agreement on the first day of the signing period.
That could help pave the way for the pact to become effective long before the original 2020 deadline possibly this year though countries must first formally approve it through their domestic procedures.
"We are within striking distance of having the agreement start years earlier than anyone anticipated," Brian Deese, an adviser to President Barack Obama, said in a speech last week at Reed College in Portland, Oregon.
The US and China, which together account for nearly 40 per cent of global emissions, have said they intend to formally join the agreement this year. It will enter into force once 55 countries representing at least 55 per cent of global emissions have done so.
"There's incredible momentum," former New Zealand Prime Minister Helen Clark, who heads the UN Development Program, told The Associated Press. "We're moving as quickly as possible to action."
She said her agency is working with more than 140 countries on climate change-related issues, and that financing to make the Paris Agreement a reality is "critical, and let's hope everyone lives up to commitments made."
The agreement, the world's response to hotter temperatures, rising seas and other impacts of climate change, was hammered out in December outside Paris.
The pact was a major breakthrough in UN climate negotiations, which for years were bogged down with disputes between rich and poor countries over who should do what to fight global warming.
The mood was so pessimistic after a failed 2009 climate summit in Copenhagen, Denmark, that UN climate chief Christiana Figueres said she thought a global deal wouldn't happen in her lifetime. Now she expects the Paris Agreement to take effect by 2018.
Under the agreement, countries set their own targets for reducing emissions of carbon dioxide and other greenhouse gases. The targets are not legally binding but countries must update them every five years.
