"Little Boy"
A US atomic bomb nicknamed "Little Boy" was dropped by a US Army Air Force B-29 bomber on August 9, 1945, over Hiroshima, Japan. LOS ALAMOS SCIENTIFIC LABORATORY

Under the leadership of President Harry S. Truman, the United States detonated the atomic bomb twice over two Japanese cities 78 years ago. Once over Hiroshima, and once over Nagasaki.

On the sixth of August 1945, the bomb, "Little Boy", was dropped at 8:15 am Hiroshima time, causing 80,000 deaths within minutes. Three days later on August 9th, "Fat Man", a second atomic bomb, was detonated over Nagasaki. 39,000 died within a minute, with a further 25,000 injured.

Japan was forced to surrender, ending the second world war definitively. The decision to use the atomic bomb is perhaps among the most controversial moves in international history. Was there a less destructive and inhumane way for the US to bring about an end to the war? Ultimately, we cannot know for sure.

Despite the enormous number of nuclear tests conducted from 1945 to 2020, nuclear weapons have never been used in active warfare since 1945. However, today, with the ongoing war in Ukraine, the possibility of their use is very much real. If Putin's invasion cannot yield success through the use of conventional military forces, will the Russian leader restrain himself from using nuclear weapons to break the Ukrainian will?

Ukraine's successful resistance creates the incentive for Putin to resort to the use of nuclear weapons as his conventional forces fail to succeed in Ukraine. One possibility that has been speculated is the use of tactical nuclear weapons by Putin. In contrast to more destructive strategic nuclear weapons, tactical nuclear weapons are designed for battlefield gains, rather than to wipe out entire cities.

As the war in Ukraine continues, Izumi Nakamitsu, the Under-Secretary-General and High Representative for Disarmament Affairs, recently delivered a message on behalf of the UN Secretary-General at the seventy-eighth anniversary of the atomic bombing of Hiroshima, Japan.

That message is that "the drums of nuclear war are beating once again" and that once more a "nuclear shadow" is being cast by international tensions, one which previously "loomed over the cold war" in the 20th century.

Nakamitsu illustrated: "Some countries are recklessly rattling the nuclear sabre once again, threatening to use these tools of annihilation."

Crucially, the message articulated the UN Secretary-General's position that "any use of nuclear weapons is unacceptable". Whilst nuclear weapons remain in the military arsenals of nation-states, governments must be committed to never deploying them Nakamitsu explained.

The UN Secretary-General's message echoed the position articulated by the G7 earlier this year. The 2023 G7 leaders summit was held in Hiroshima, with member-states articulating their "commitment to achieving a world without nuclear weapons" as well as "the importance of the 77-year record of non-use of nuclear weapons".

However, whilst these words indicate a clear consensus within the Western international community that a first strike would be unacceptable, with regard to a second strike, things are not so simple. For example, in Britain, pressure has been put on politicians to commit to the use of Trident in response to a nuclear attack on Britain. Without this commitment, the implication is that the deterrent value of our nuclear capabilities is redundant.

Going back to the UN Secretary-General's message, the statement that "any use of nuclear weapons is unacceptable" does not grant exceptions for those subject to the dilemma of whether to deploy a second strike in response to a first.

Crucially, a world in which the chance of nation-states deploying nuclear strikes against each other is zero requires a successful process of nuclear disarmament amongst the global international community. Accordingly, the Under-Secretary-General explained that "disarmament is at the heart of the recently launched policy brief on a New Agenda for Peace".

The agenda demands that UN members "urgently recommit to pursuing a world free of nuclear weapons and to reinforce the global norms against their use and proliferation." Moreover, Nakamitsu explained: "The only way to eliminate the nuclear risk is to eliminate nuclear weapons."

Right now, with the ongoing war in Ukraine and the tensions between Russia, Ukraine, and the West, the prospects of a nuclear-free world developing anytime soon are clearly slim. However, the problems facing a move towards a nuclear-free world go deeper than the conflict over Ukraine.

Human civilisation is currently characterised by a multi-polar world order in which the United States is being challenged by an authoritarian China seeking to assert itself on the world stage. Other rising powers include Brazil, India, and South Africa, who together with China and Russia make up the "BRICS". Indeed, tensions also exist between these rising powers. For example, tensions between India and China have escalated over border disputes in the Himalayan region.

However, perhaps the international trend towards multipolarity only underscores the importance of the UN Secretary General's message. In other words, because competition amongst emerging powers and great powers is a key feature of the current international system, a commitment to nuclear disarmament is essential to ensure geopolitical tensions do not escalate out of control.