A large number of national representatives currently attending the General Assembly in New York have already signed the UN Treaty on the Prohibition of Nuclear Weapons. They seek a world free from "doomsday weapons," as secretary-general Antonio Guterres put it. Yet the nuclear powers themselves have so far refused to sign on.

Who has nuclear weapons and how many do they have?

It is assumed that nine countries possess nuclear weapons: The United States, Russia, France, the United Kingdom, China, India, Pakistan, Israel and North Korea. A report published earlier this year by the Stockholm International Peace Research Institute (SIPRI) says that these countries possess a total of roughly 15,000 nuclear warheads. These, however, are very unevenly distributed among the nine nuclear powers. The US and Russia possess some 93 percent of those warheads.

Which countries are officially nuclear powers?

Those countries that are signatories of the original 1968 Nuclear Non-Proliferation Treaty: These are, in order of their initial attainment of nuclear weapons: the US (1945), the Soviet Union/Russia (1949), Great Britain (1952), France (1960) and China (1964).

The remaining four possess nuclear weapons but are not signatories of the Nuclear Non-Proliferation Treaty. North Korea was temporarily part of the treaty, but withdrew from it in 2003. Israel has never officially admitted to having a nuclear bomb but experts are certain that it does.

How has the number of nuclear warheads around the globe changed over the years?

Although more and more states have attained or developed nuclear weapons over the course of time, there are markedly fewer nuclear warheads today than there were during the Cold War. Some 70,000 existed in the 1980s. The number of warheads is shrinking today as well. The reason for that is the New START nuclear disarmament treaty signed by the United States and Russia in 2010. On the other hand, there is more to the problem than just numbers. Almost all of the countries that possess nuclear warheads continue to modernize them and make them more powerful.

What steps have been taken toward nuclear disarmament?

The earliest initiative was the Nuclear Non-Proliferation Treaty. Signatory states that possessed nuclear weapons obliged themselves to eventually rid themselves of them. The official nuclear powers took steps to negotiate disarmament in the treaty. Nevertheless, the treaty did little to stop the further spread of nuclear weapons.

Furthermore, the treaty has one major flaw, the fact that the world is divided between those countries that have nuclear weapons and those that do not. Critics of the Nuclear Non-Proliferation Treaty also see the fact that the original five signatories are permanent members of the UN Security Council as a major problem.

Have there been successful nuclear disarmament treaties?

More than any other nuclear powers, the US and the Soviet Union/Russia have dismantled large numbers of warheads and delivery systems since the end of the Cold War. In the early 1990s, both sides agreed to reduce their nuclear arsenals by signing the Strategic Arms Reduction Treaty (START).

The treaty stalled a number of times over the following years but its aims were nonetheless important enough that Presidents Barack Obama and Dmitry Medvedev agreed to follow START I and START II with the New START treaty, which they signed in 2010. Obama went so far as to outline his vision for a world free from nuclear weapons. In light of current President Donald Trump's policy of military strength and Russia's aggressions in Ukraine, the fate of START's future has become uncertain.

Which countries have given up their nuclear ambitions?

Iran renounced any military use of nuclear technology as part of an international agreement in 2015, which is supervised by the International Atomic Energy Agency (IAEA), however Israel and the Trump administration claim it is not honoring that agreement. South Africa abandoned the further development of its nuclear arms program before the end of apartheid, and Libya ended its nuclear aspirations under Moammar Gadhafi. Three Post-Soviet states: Ukraine, Kazakhstan and Belarus, also represent an exceptional case. They all signed START I with the US, promising to dismantle nuclear stockpiles accumulated during their time in the Soviet Union. All three lived up to that commitment. More than any, Ukraine, at that time, possessed a massive nuclear arsenal.

In the wake of Russian aggression in Ukraine, however, critics point to the drawbacks that this type of relinquishment can have: They argue that had Ukraine kept its nuclear weapons it would have deterred Russia from annexing the Crimean Peninsula.

Others, such as disarmament expert Oliver Meier of the German Institute for International and Security Affairs (SWP), think that North Korea's example could "set off a dangerous political chain reaction, in which other states more forcefully pursue a course of nuclear deterrence, going so far as to attain nuclear weapons themselves," as he recently told DW.

What are the chances that there will be a ban on nuclear weapons?

This most recent initiative, officially known as the Treaty on the Prohibition of Nuclear Weapons, is nothing more than symbolic in the end, as none of the world's nine nuclear powers want anything to do with it. They argue that having nuclear weapons is the best defense against potential attack. Furthermore, they point to the Nuclear Non-Proliferation Treaty. That treaty, though, does not ban nuclear weapons.

NATO is not convinced about the initiative either. An official reaction released by the Western military alliance stated: "This initiative clearly disregards the realities of the international security environment." Jean-Yves Le Drian, foreign minister of official nuclear power France, called the initiative "wishful thinking," indeed "almost irresponsible," adding that it would do nothing more than weaken the original Nuclear Non-Proliferation Treaty.

In contrast, Beatrice Fihn, director of the International Campaign to Abolish Nuclear Weapons (ICAN), called for all nations to sign the treaty. Saying that nuclear weapons are "the only weapons of mass destruction that are not illegal, despite their immense destructive power and the threat that they pose to humanity." Fihn says that with Donald Trump in the White House, that threat has only increased.