The end of World War II saw the beginning of a “cold war” and a nuclear arms race. In 1963, a treaty banning nuclear testing in the atmosphere, outer space, and under water was signed but underground nuclear testing still continued. The General Assembly adopted resolution 50/245, the Comprehensive Nuclear Test-Ban Treaty, on 10 September 1996. The Treaty bans all nuclear testing - surface, atmosphere, underwater and underground. As of 2019, 168 countries have ratified the Comprehensive Nuclear Test-Ban Treaty but it has not yet entered into force.
Parties to the 1992 United Nations Framework Convention on Climate Change agreed the emission reductions provisions in the Convention were insufficient. Work began on negotiating a protocol to create stricter limits for reducing greenhouse-gases. On 11 December 1997, the Kyoto Protocol to the United Nations Framework Convention on Climate Change was adopted unanimously. The Kyoto Protocol set internationally binding emission reduction targets. Developed countries, accepted as being more responsible for the high levels of greenhouse gas, were given higher targets levels to achieve.
In 1945, the governments of the Allied powers created the International Military Tribunal for the prosecution of the World War II criminals. In the 1990's, the situations in the former Yugoslavia and Rwanda compelled the UN to establish tribunals to bring justice to victims. But these tribunals were set up to deal with specific conflicts during a specific time period. The groundwork for a permanent criminal court began with the adoption of the Rome Statute of the International Criminal Court (ICC), on 17 July 1998 at an UN diplomatic conference held in Rome. The Rome Statute provided the legal basis for establishing a permanent international criminal court and entered into force on 1 July 2002. The ICC investigates, prosecutes and tries individuals accused of committing the most serious crimes of concern to the international community: genocide, crimes against humanity, war crimes, and crimes of aggression.
On 30 August 1999, the people of East Timor voted for independence over special autonomy within the Republic of Indonesia. The United Nations Transitional Administration in East Timor (UNTAET) was established by the Security Council several months later to administer over East Timor during its transition to independence. When East Timor became independent on 20 May 2002, Secretary-General Kofi Annan handed over authority from the UN to the Speaker of East Timor's National Parliament. UNTAET, its mandate fulfilled, was succeeded by the United Nations Mission of Support in East Timor (UNMISET). East Timor, now known as Timor-Leste, became the 191st Member of the United Nations in 1999.
In September 2000, the Millennium Summit was held at the UN Headquarters in New York. The theme was “The United Nations in the twenty-first century” and it encompassed topics of peace and security: disarmament; development, poverty eradication, human rights, and strengthening the UN. World leaders came together in the General Assembly and adopted the United Nations Millennium Declaration, resolution 55/2. The Declaration states “At the dawn of a new millennium, to reaffirm our faith in the Organization and its Charter … We recognize that, in addition to our separate responsibilities to our individual societies, we have a collective responsibility to uphold the principles of human dignity, equality and equity at the global level.” The Declaration committed world leaders to new global partnerships and set out a series of time-bound targets - with a deadline of 2015 - that become known as the Millennium Development Goals.
At the end of 2000, 36.1 million people were living with HIV/AIDS and 3 million people had died of AIDS. In an address to African leaders, UN Secretary-General Kofi Annan stated the battle against AIDS was a “personal priority”. A special session of the General Assembly, focusing on an expanded global response to the HIV/AIDS epidemic, was held in New York in June 2001. One hundred and eighty-nine UN Member states adopted the Declaration of Commitment on HIV/AIDS. With this declaration world leaders committed themselves to setting common targets for reducing the spread of HIV and alleviating its impact.
From 8 to 10 May 2002 the General Assembly for the first time held a special session devoted entirely to children. The session included over 600 children as delegates and participants, another first for a UN meeting. Secretary-General Kofi Annan opened the session, addressing the world’s children, by stating "We, the grown-ups, have failed you deplorably". On the final day of the special session, world leaders adopted the plan of action known as "A World Fit for Children". The plan included 21 specific goals and targets in four priority areas: promoting healthy lives; providing quality education; protecting against abuse, exploitation and violence; and combating HIV/AIDS.
In 2003, the United Nations looked to ensure that the benefits of new technologies - especially information and communications technologies, were available to all. Secretary-General Ban Ki-moon stated, “The swift emergence of a global 'information society' is changing the way people live, learn, work and relate...yet too many of the world's people remain untouched by this revolution. A 'digital divide' threatens to exacerbate already-wide gaps between rich and poor, within and among countries.” In December, the first phase of the World Summit on the Information Society was held in Geneva. At the Summit, international organizations, governments, the private sector, and civil society came together and adopted a Declaration of Principles and Plan of Action that outlined specific goals for bridging the digital divide.
On 19 August 2003, a truck bomb exploded at the UN headquarters in Baghdad, killing the top United Nations envoy in Iraq, Sergio Vieira de Mello, and 21 others. Secretary-General Kofi Annan denounced the bombing as an inexcusable "act of unprovoked and murderous violence." A month later, on 22 September, another suicide bomber struck a police checkpoint outside the UN headquarters killing an Iraqi policeman and wounding nineteen people, including two UN workers. After the second attack Secretary-General Annan announced the creation of a High-Level Panel on Threats, Challenges, and Change. On 2 December 2004, "A More Secure World: Our Shared Responsibility", was published by the Panel. It made recommendations for change in six areas identified as the greatest threats to security in the 21st century: poverty & environmental degradation, terrorism, civil war, conflict between states, the proliferation of weapons of mass destruction, and organized crime.
In a 2005 report, Secretary-General Kofi Annan proposed the establishment of a Peacebuilding Commission in response to the “gaping hole in the United Nations institutional machinery: no part of the United Nations system effectively addresses the challenge of helping countries with the transition from war to lasting peace”. On 20 December 2005, both the General Assembly and the Security Council passed resolutions to create the Peacebuilding Commission. The purpose of the Commission is to “bring together all relevant actors to marshal resources and to advise and propose integrated strategies for post-conflict peacebuilding and recovery”.