In the complex arena of international relations, the use of force remains one of the most contentious issues governed by public international law. The legal parameters defining when and how force may be employed are crucial for maintaining global peace and security. These rules are primarily enshrined in the United Nations Charter and various customary international law doctrines. However, evolving geopolitical landscapes and the emergence of new kinds of conflicts pose significant challenges to these established norms.

Legal Foundations
The foundational legal framework for the use of force is articulated in the United Nations Charter, which was ratified in 1945. Article 2(4) of the Charter prohibits the threat or use of force against the territorial integrity or political independence of any state. The only exceptions to this prohibition are the scenarios outlined in Article 51, which permits the use of force in self-defense if an armed attack occurs against a Member State, and those actions authorized by the UN Security Council under Chapter VII of the Charter as measures to maintain or restore international peace and security.

Self-Defense and Collective Security
Self-defense, as mentioned, allows a state to use force in response to an armed attack until the Security Council can take measures necessary to maintain international peace and security. The concept of an "armed attack" can include traditional military attacks and, more contentiously, cyber- attacks if they are sufficiently damaging.

Collective security is another critical aspect where the UN can authorize force to counteract aggression or breaches of peace. Notable instances include the Korean War in the 1950s and the 1991 Gulf War, where UN coalitions forcibly responded to invasions in South Korea and Kuwait, respectively.

Challenges and Controversies
One of the primary challenges in applying international law to the use of force is the interpretation of what constitutes an "imminent threat." The concept of preemptive self-defense or anticipatory self-defense allows for the use of force in response to an imminent attack. However, defining "imminence" has been highly controversial. The 2003 invasion of Iraq by the United States, justified by the Bush administration as necessary to prevent Saddam Hussein from using alleged weapons of mass destruction, sparked significant international debate about the limits of this doctrine.

Humanitarian Intervention
Another contentious issue is humanitarian intervention, which is the use of force to stop severe human rights violations, such as genocide or crimes against humanity, even without Security Council authorization. The NATO intervention in Kosovo in 1999 is often cited as an example. Although not explicitly authorized by the UN Security Council, many considered it morally justified to prevent further ethnic cleansing. However, without UN endorsement, such actions challenge the principles of non-interference and sovereignty.

Recent Trends and Data
Recent conflicts highlight the ongoing complexities of applying international law to the use of force. According to the Stockholm International Peace Research Institute (SIPRI), the number of armed conflicts has increased in the last decade, with major wars in Syria, Yemen, and Ukraine involving both state and non-state actors. This resurgence of conflict underscores the difficulty of maintaining peace and security in a multipolar world where power dynamics are continuously shifting.

In terms of data, the UN reports show a significant number of vetoes in the Security Council that have prevented action in situations like Syria, where the use of force might have been considered under the collective security system. The deadlock often leads to unilateral actions or coalition-led interventions without Security Council approval, complicating the legal landscape.

Conclusion
The use of force in international law is governed by a framework designed to maintain international peace and uphold sovereignty and territorial integrity. However, the interpretation and application of these laws in contemporary conflicts reveal significant challenges. As global power dynamics continue to evolve, and as new forms of warfare emerge, the international community must reassess and possibly reform the existing legal structures to prevent misuse of force and ensure effective response to global security threats. The commitment to a rules-based international order is fundamental to achieving lasting global peace and security.