Global leaders are set to sign the landmark Paris Agreement on climate change at the United Nations Headquarters in New York.
China and the United States, the world's no.1 and no. 2 greenhouse gas emitters, on Friday signed the Paris climate deal at a UN ceremony attended by a record 171 countries, boosting hopes of quick action on combating global warming.
The two countries together account for nearly 40 percent of global emissions. The agreement will enter into force once 55 countries representing at least 55 percent of global emissions have formally joined it.
"This is a moment in history," UN Secretary General Ban Ki-moon said. He announced that 171 countries were set to sign the accord.
“Record global temperatures. Record ice loss. Record carbon levels in the atmosphere. We are in a race against time,” the UN chief told the gathering.
"The era of consumption without consequences is over. We must intensify efforts to decarbonize our economies. And we must support developing countries in making this transition. The poor and most vulnerable must not suffer further from a problem they did not create," the UN secretary general said.
Many now expect the climate agreement to enter into force long before the original deadline of 2020. Some say it could happen this year.
The Paris Agreement, the world's response to hotter temperatures, rising seas and other impacts of climate change, was reached in December 2015 as a major breakthrough in UN climate negotiations, which for years were slowed by disputes between rich and poor countries over who should do what.
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.
Fossil fuels, the biggest source of man-made pollutant gases, are still used much more widely than clean renewable sources like wind and solar power.
