NEW YORK: The United Nations is all set to adopt a global treaty banning nuclear weapons today despite the opposition from the United States, Britain, France and other nuclear powers that boycotted negotiations. Supporters of the treaty describe it as a historic achievement but the nuclear-armed states have dismissed the ban as unrealistic, arguing it will have no impact on reducing the global stockpile of 15,000 nuclear weapons. Led by Austria, Brazil, Mexico, South Africa and New Zealand, 141 countries have taken part in three weeks of negotiations on the treaty that provides for a total ban on developing, stockpiling or threatening to use nuclear weapons. Advocates hope it will increase pressure on nuclear states to take disarmament more seriously. This will be a historic moment, Costa Rica’s ambassador, Elayne Whyte Gomez, the president of the UN conference on the treaty, said on the eve of the adoption. The world has been waiting for this legal norm for 70 years, she said, calling it a response for humanity. None of the nine countries that possess nuclear weapons the United States, Russia, Britain, China, France, India, Pakistan, North Korea and Israel took part in the negotiations.