At the beginning of the 21st century, we face a world of extraordinary challenges—and of extraordinary interconnectedness. We are all vulnerable to new security threats, and to old threats that are evolving in complex and unpredictable ways. Either we allow this array of threats, and our responses to them, to divide us, or we come together to take effective action to meet all of them on the basis of a shared commitment to collective security.

Late last year, convinced that the time had come for a fundamental review of our collective security system, I established a High-Level Panel on Threats, Challenges and Change. I asked its 16 members—eminent people, representing many nations and points of view (see box below)—to analyse the threats to peace and security our world faces; to evaluate how well our existing policies and institutions are meeting them; and to recommend changes to those policies and institutions, so as to ensure an effective collective response to those threats.

Their report, “A More Secure World: Our Shared Responsibility”, which I received this week, follows a year of consultations around the world. It makes 101 far-sighted but realistic recommendations. If acted on, they would address the security concerns of all states, ensure that the UN works better, strengthen the international rule of law and make all people safer.

A world of interconnected threats

We must first agree on the threats we face. Today, any event or process that leads to deaths on a large scale or the lessening of life chances, and which undermines states as the basic unit of the international system, should be viewed as a threat to international peace and security.

According to the panel, six clusters of threats fall under that rubric: economic and social threats, including poverty and deadly infectious disease; inter-state conflict and rivalry; internal violence, including civil war, state collapse and genocide; nuclear, radiological, chemical and biological weapons; terrorism; and transnational organised crime.

Today, these threats are interconnected to an unprecedented degree, and no state acting alone can defeat them. The panel report spells out the dangers with horrifying clarity. With the amount of highly enriched uranium that could fit into six milk cartons, a terrorist could improvise a nuclear device to level a medium-sized city. A nuclear attack on such a city in the United States or Europe would have staggering costs for the world economy. According to the World Bank, the attacks of September 11th 2001 cost more than $80 billion dollars and pushed 11m people in developing countries into poverty. The economic fallout from a nuclear terrorist attack would dwarf these numbers. Given the relationship between poverty and infant mortality, we would count the cost of a nuclear terrorist attack in a rich country in two terrible death tolls: in the attacked city, and in poor nations all over the world.

Likewise, the security of developed countries is only as strong as the ability of poor states to respond to and contain a new deadly infectious disease. As the panel notes, the incubation period for most infectious diseases is longer than most international air flights. As a result, any one of the 700m people who travel on airlines in a year could unwittingly carry a lethal virus to an unsuspecting country. The 1918 influenza epidemic killed twice as many people in one year as HIV/AIDS has killed in the past 28 years. Today, a similar virus could kill tens of millions in a fraction of the time.

So, in today's world, any threat to one is truly a threat to all. This principle, once applied only to military attacks by one state against another, should be extended to all categories of threats we face. And since there are real limits on self-protection, all states share an interest in a collective-security system that commits all of them to act co-operatively against these dangers.

Getting serious about prevention

Given the gravity and interconnectedness of today's threats, our world needs to be far more committed to prevention. Prevention, if properly resourced and broadly supported, can be highly effective. The panel report reminds us that in 1963, many thought that 25-50 states would possess nuclear weapons by this year; the Nuclear Non-Proliferation Treaty has helped prevent this. The World Health Organisation, which led efforts to eradicate smallpox and roll back the threat of polio, recently helped halt the spread of SARS and save the lives of tens of thousands of people.

The best agents of prevention are capable states, exercising their sovereignty responsibly, dealing with internal dangers before they threaten others, and acting collectively with other states to meet threats on a global scale.

And our best preventive strategy is to support development. Committing resources to achieve the Millennium Development Goals agreed in 2000 (which, among other things, set targets to halve extreme poverty and hunger by 2015) is the best security investment states can make. It will save lives in poor countries, reduce violent conflict and the appeal of radicalism, and bolster the ability of states to deal with threats before they cause real harm.

The dangers of inadequate preventive action are powerfully illustrated by the HIV/AIDS epidemic. In the face of a lamentably slow and ineffective global response, the disease has killed 20m people in as many years, and it continues to spread. Tragically, the worst is yet to come. Its ultimate cost will be measured not just in lives, but in shattered societies. Despite greater international resolve in recent years, we are still not taking all the steps needed to bring the disease under control.

We also need a major initiative to build public-health capacities in the developing world. If diseases can be treated and, better still, prevented at local level, not only the poorer countries will benefit. The whole world will acquire better defences against bio-terrorism and large-scale natural epidemics. And the Security Council should work closely with the World Health Organisation to strengthen biological security through prompt, effective responses to such outbreaks.

Equally critical is greater collective action on environmental degradation—from a long-term strategy to reduce global warming, going beyond the period covered by the Kyoto protocol, to better management of natural resources in countries that are at risk.

Countering terrorism

Prevention is also a vital part of any effective strategy to protect people against terrorism. Terrorism is not new. What is new is the range, scale and intensity of the threat. Today, one terror network, al-Qaeda, has the capacity to kill around the world, and has struck in more than ten UN member states in the past few years. In addition, the prospect that terrorists could acquire instruments of massive destruction creates unprecedented dangers.

The UN must make better use of its assets in the fight against terrorism. It should articulate an effective and principled counter-terrorism strategy that is respectful of the rule of law and universal human rights. But first—a significant problem—terrorism must be defined. One of the panel's signal achievements is to offer such a definition, agreed to by all the panellists. It would define terrorism as any action intended to kill or seriously harm civilians or non-combatants, with the purpose of intimidating a population or compelling action by a government or international organisation. States should use this definition to build consensus and strengthen the UN 's response to this deadly scourge.

The report also makes urgent recommendations on non-proliferation, disarmament, and curbing the supply of dangerous materials to reduce the risk of nuclear, chemical or biological attacks by states or terrorist groups. States must be encouraged to give up the development of domestic uranium enrichment, and be urged to take part in a voluntary time-limited moratorium on the construction of reprocessing plants. The International Atomic Energy Agency's ability to monitor compliance with the Non-Proliferation Treaty should be strengthened, using the standards in the treaty's additional protocol for safeguards inspections.

Civil and interstate wars

Since the end of the cold war, the UN has become far more engaged in preventing and ending civil wars, and it has continued its long-standing role of working to stop wars between states. As the panel points out, more civil wars have been brought to an end through negotiation since 1990 than in the 200 years before that. Through successes and failures, we have developed expertise and learned hard lessons.

As the demand for UN blue helmets continues to grow, we need to boost the supply of peacekeepers to avoid repeating some of the worst failures of the 1990s. Wealthy states should hasten their efforts to transform existing forces into contingents suitable for peace operations, and put them at the disposal of the UN . We must also invest in mediation and support the implementation of peace agreements. The report stresses the importance of demobilising combatants and reintegrating them into civilian life. If this is not done, civil wars cannot be successfully brought to an end, and other critical goals—democracy, justice and development—will remain unmet.

Time and again, the international community has lost focus once the high point of a crisis has passed or peacekeepers have left a country. I welcome the panel's proposal to help deal with this problem: the creation by the Security Council of a Peacebuilding Commission, which would give the organisation a strategic focus for its work in countries under stress or emerging from conflict.

The use of force

Prevention or peaceful dispute-resolution will sometimes fail. When it does, we must be able to rely on the use of force. No matter what the cause, the report proposes five basic guidelines that all states, and the Security Council, should bear in mind in deciding whether to do so:

• Seriousness of threat : Is the threat serious enough to justify prima facie the use of force?
• Proper purpose : Is the primary purpose of the proposed use of force to halt or avert the threat in question?
• Last resort : Has every non-military option been explored and exhausted?
• Proportional means : Is the force proposed the minimum necessary to meet the threat?
• Balance of consequences : Is it clear that the consequences of action will not be worse than the consequences of inaction?

The report sees no need to amend Article 51 of the UN Charter, which preserves the right of all states to act in self-defence against armed attack, including the right to take pre-emptive action against an imminent threat.

However, in the new security environment in which we live, states may also fear threats that are neither imminent nor proximate, but which could culminate in horrific violence if left to fester. The Security Council is already fully empowered by the charter to deal with these threats. It must be prepared to do so, taking decisive action earlier than in the past, when asked to act by states that have based their claims on reliable evidence.

The question of action to protect civilians inside states has long been fraught with controversy. Yet it is being recognised more and more widely that the question is better framed not as one of a right to intervene, but of our responsibility to protect—a responsibility borne, first and foremost, by states. The panel members, whose background and experience vary widely, have agreed that the principle of non-intervention in internal affairs cannot be used to protect those who commit genocide, large-scale ethnic cleansing, or other comparable atrocities. I hope UN members will share that view—and that the Security Council will act on it.

A new United Nations

What does the panel's report mean for the UN ? The organisation is now nearly 60 years old. It was born in a very different time and designed for a very different world. It has an under-appreciated record of adapting to new dangers—take, for instance, its peacekeeping efforts in civil wars around the world, and its response to the attacks of September 2001. But it clearly needs far-reaching reform if it is to prevent and respond to all the threats that we face today.

Some propose that a collective response through the UN is too difficult or not necessary. But action taken to meet threats always has an impact beyond the immediate context, and all states benefit from a shared global framework. That does not mean that the UN needs to do everything. Indeed, as a matter of good policy and sheer practicality, the UN must learn to share burdens, welcoming help from others and working hand in hand with them. I am pleased that it is already doing so—and that the panel's report makes sensible recommendations to strengthen the UN 's partnerships with regional organisations and individual member states.

Inevitably, great attention will fall on the question of Security Council reform. What are the objectives of such reform? They surely must be to make the council more effective and authoritative. The idea of permanent membership was devised to ensure the active engagement of the big powers of 60 years ago in the maintenance of international peace and security. Whether we need new permanent members is a matter of controversy and debate.

The report offers two formulae for consideration by member states, both of which would expand membership to 24, and would have the same goals: to bring into the council's deliberations those who contribute most to the organisation financially, militarily and diplomatically; to ensure that the council broadly represents the membership of the UN as a whole; and not to expand the veto, which would render decision-making more difficult. The panel's proposals offer a chance for a breakthrough on this vital issue in the year ahead. If its recommendations are acted upon, the new Security Council would be more representative of our world, and better equipped to take decisive action.

We also need a strengthened UN secretariat, one that can support the new Peacebuilding Commission and implement more effectively the decisions of the Security Council and other inter-governmental bodies on everything from peacekeeping operations to mediating civil wars. The report envisages a secretariat that is more concerted in its action, and in which the secretary-general has more responsibility for management and greater accountability.

An equally important proposal is to overhaul the Economic and Social Council, to strengthen its role in social development and in improving knowledge about the economic and social dimensions of security threats. The report also recommends changes to make the Human Rights Commission a better defender of the human rights of people everywhere.

Time to decide

In his last annual address to Congress in January 1945, Franklin Roosevelt, then America's president, alluded to his plans to create a new collective security institution, the United Nations, and gave warning that: “In our disillusionment after the last war, we gave up the hope of achieving a better peace because we had not the courage to fulfil our responsibilities in an admittedly imperfect world.”

Almost exactly 60 years later, we once again find ourselves mired in disillusionment, in an all too imperfect world. It is easy to stand at the sidelines and criticise. And we could talk endlessly about UN reform. But our world no longer has that luxury. The time has come to adapt our collective security system, so that it works efficiently, effectively and equitably.

Next year, UN member states will be reviewing progress in implementing the Millennium Declaration adopted in 2000, culminating in a summit of world leaders in New York in September. This will be an appropriate moment for them to act on some of the most important recommendations in the panel's report, which require decisions at the highest levels of government. I shall indicate which recommendations call for decisions at that level, in my view, in a report of my own early next year.

I fervently hope that world leaders will rise to this challenge. In the past three years we have all lived through a period of deep division and sombre reflection. We must make 2005 a year of bold decision. As the panel simply puts it: “We all share responsibility for each other's security.” Let us summon the courage to fulfil that responsibility.