Forecasting the Fifth Wave: Emerging Terrorist Threats in a Changing World
The international defense community consistently struggles to predict the changing landscape of global terrorism. Counterterrorism practitioners have frequently been reactive rather than proactive, while the academic community has faced challenges in developing models that reflect terrorism’s complex and dynamic nature. These deficiencies led to the failure to anticipate and prevent major terrorist incidents such as the September 11 attacks in 2001, the 2002 Bali bombings, the 2015 Paris attacks, and most recently, Hamas’s coordinated attacks on October 7, 2023. This article builds on David Rapoport’s theory of the “four waves” of terrorism to explore a potential “fifth wave.” Analysis of data from the Global Terrorism Trends and Analysis Center (GTTAC) indicates that the strongest candidates for this fifth wave are the continuation of the religious wave—especially the Salafi-jihadist interpretation, and the activities of Iran-backed terrorist groups.
Four Waves of Terrorism
David Rapoport’s theory of the four waves of modern terrorism presents a typology grounded in political orientation and influenced by the historical, cultural, and ideological conditions of distinct periods characterized by heightened terrorist activity. A “wave” denotes a generational cycle of terrorism unified by a shared ideological drive, with revolutionary change serving as the central objective in each phase. Rapoport identifies four major waves: the Anarchist (1880–1920), Anti-Colonial (1920–1960), New Left (1960–1980), and Religious (1980–ongoing).
The first, the Anarchist Wave began in Russia and is widely recognized as the starting point of modern terrorism. It emerged from deep dissatisfaction with the slow pace of political reform, particularly frustration with entrenched authoritarian systems and the persistence of state power, which anarchists sought to dismantle in favor of stateless, egalitarian alternatives, and was characterized by the tactical use of dynamite and the assassination of high-ranking officials, including heads of state. This period became known as the “Golden Age of Assassinations,” during which a major political figure was killed approximately every 18 months. Notably, women played an active and significant role in this wave. Examples include the assassination of U.S. President William McKinley in 1901 by Leon Czolgosz, King Umberto I of Italy in 1900 by Gaetano Bresci, and Russian Tsar Alexander II in 1881 by members of the anarchist group Narodnaya Volya.
The second wave of modern terrorism, known as the Anti-Colonial Wave, spanned from the 1920s to the 1960s and emerged in the aftermath of World War I with the signing of the Treaty of Versailles. The treaty’s emphasis on the principle of self-determination, which facilitated the breakup of defeated empires, provided the ideological foundation for a new form of terrorism centered on national liberation. Unlike the preceding Anarchist Wave, anti-colonial groups such as the Irish Republican Army (IRA), the National Liberation Front (FLN) in Algeria, and the Jewish Irgun in Mandatory Palestine relied less on targeted assassinations and focused more on eliminating police officers and military personnel as part of their strategy. Diaspora communities in Europe and in the United States often provided strong support to these movements, offering financial resources and political backing. During this period, many such actors gained recognition as “freedom fighters,” reflecting the relative international sympathy for anti-colonial struggles.
The third wave of modern terrorism, known as the New Left Wave, emerged between the 1960s and 1980s, heavily influenced by the Vietnam War and a broader anti-imperialist sentiment. This period revealed the vulnerability of modern states to relatively unsophisticated weapons and tactics, which various militant groups used effectively. A dramatic increase in international terrorist activity marked this wave, and high-profile individuals once again became frequent targets. Between 1968 and 1982, there were approximately 700 hijackings and 409 international kidnapping incidents involving 951 hostages. A key objective of many groups was to provoke a disproportionate response from governments, thereby gaining attention and support for their causes. Notably, one-third of all targets during this wave were associated with the United States. Unlike the Anti-Colonial Wave, where many militants were labeled “freedom fighters,” this terminology fell out of favor, particularly within the United Nations. In response to the rise in transnational attacks, international cooperation in counterterrorism efforts increased significantly.
The fourth wave of modern terrorism, known as the Religious Wave, began in 1979 and continues to the present day. Two pivotal events sparked this wave: the Iranian Revolution and the Soviet invasion of Afghanistan. These developments intensified the role of religion in political violence and created fertile ground for the rise of militant religious movements. Groups associated with this wave draw upon sacred texts and religious revelations to legitimize their actions, often framing their violence as divinely mandated. A defining characteristic of this era has been the widespread use of suicide bombings and attacks aimed at causing mass casualties.
While much of the focus has been on Islamist groups, this wave is not confined to one religion. For example, the Japanese cult Aum Shinrikyo employed chemical weapons in the 1995 Tokyo subway attack. Similarly, white supremacist groups such as the Christian Identity movement have invoked distorted interpretations of Christianity, claiming that God is white, and used select biblical passages to justify acts of violence like hate crimes and domestic terrorism. A central figure in this wave was Usama Bin Laden, who viewed the presence of U.S. military bases in Saudi Arabia as intolerable, helping catalyze the formation of al-Qaeda. The emergence of Salafi-jihadist groups such as al-Qaeda and the Islamic State (ISIS) further exemplifies the global spread and ideological intensity of religiously motivated terrorism in this ongoing wave.
Building on this historical foundation, scholarly analyses often failed to anticipate the long-term consequences of the Soviet invasion of Afghanistan, particularly its role in facilitating the mobilization of mujahideen fighters and the eventual formation of al-Qaeda. Furthermore, the emergence of ISIS as an offshoot of al-Qaeda in Iraq, following the U.S.-led invasion, caught many analysts by surprise. Together, these critical turning points catalyzed the transnational spread of jihadist movements across the Middle East, South and Southeast Asia, and Africa.
In this broader context of unintended consequences and evolving threats, the Arab Spring, initially seen as a democratizing force across the Middle East and North Africa (MENA) region, inadvertently created political vacuums in several states. Instead of leading to stable democratic transitions in countries like Syria, these power vacuums offered fertile ground for extremist groups to gain influence and territorial control. This transformation further illustrates the resilience and adaptability of the Religious Wave. Compounding these developments, Western countries have faced an increasing threat from self-radicalized individuals and lone-actor terrorism, fueled by online propaganda and decentralized extremist networks.
Although the fourth wave of terrorism continues, questions remain about what form the fifth wave might take—whether it will be driven by resilient Salafi-jihadist movements, Iran-backed terrorist groups, or emerging ideological currents such as right-wing extremism. While nuclear terrorism and cyberterrorism are often discussed in this context, they represent methods rather than the type of unifying ideology that defines a wave in Rapoport’s model.
Salafi-Jihadist Terrorism
Salafism, described by Joas Wagemakers as a diverse and multifaceted movement, is rooted in the belief that the first three generations of Muslims—known as al-salaf al-salih—represent the purest form of Islamic practice. Citing a hadith from Sahih al-Bukhari (8:76:437), Salafists view these early followers as exemplary and aim to closely replicate their way of life. This commitment leads to a strict, literal interpretation of the Quran and sunnah, which are seen as fully sufficient for guiding Muslim life. Salafists reject later religious innovations (bid‘ah) and contemporary interpretations of Islam. Central to their doctrine is the oneness of God (tawheed) and the belief in God’s exclusive authority to legislate (hakimiyya), which results in the rejection of secular law and democratic systems. More broadly, Salafism positions itself in opposition to Western secular values.
Salafi-jihadism is a radical ideological movement that claims to represent only “true” Muslims, often labeling other Muslims who reject its strict interpretations as heretics or apostates. Adherents insist on severing all ties with individuals or groups who question or deviate from their narrow theological views, which are based on a rigid Salafi interpretation of Islamic law. Their vision of governance is rooted in enforcing this interpretation, and any resistance is considered apostasy, punishable by death. Salafi-jihadists justify the killing of Shi’ites on the grounds that they are apostates and actively target groups like the Muslim Brotherhood, whom they see as traitors for compromising with non-Muslims. Moreover, they advocate for offensive jihad against what they define as idolatry—a category that extends beyond religious polytheism to include all non-Salafi cultures, practices, and belief systems.
Al-Qaeda and its former Iraqi branch, Al-Qaeda in Iraq (AQI)—which later evolved into ISIS—are prominent examples of Salafi-jihadist terrorist organizations. The September 11, 2001, terrorist attacks triggered a global war on terrorism, prompting significant shifts in the operational strategies of both ISIS and Al-Qaeda. In response to heightened counterterrorism efforts, Al-Qaeda adopted an umbrella model, bringing various jihadist groups under its regional networks. For instance, Jama’at Nusrat al-Islam wal-Muslimin (JNIM) in the Sahel formed through the merger of four jihadist factions, while Hay’at Tahrir al-Sham (HTS) in Syria emerged from the unification of six groups. In contrast, ISIS has maintained a centralized core in Syria while simultaneously attempting to establish a presence in Somalia. It has permitted other jihadist groups to adopt the ISIS brand, provided they meet specific criteria—namely, possessing a substantial number of militants and exercising territorial control. These affiliates, however, remain only loosely connected to the central ISIS organization.
The GTTAC categorizes incidents according to twelve ideological frameworks, including jihadist, anarchist, left-wing, right-wing extremist, ethnonationalist, and Iran-backed, among others. In response to emerging security threats, the GTTAC recently expanded its classification system by adding two new categories, cartels and gangs, to monitor violence perpetrated by six newly designated transnational criminal cartels and four gangs operating primarily in Haiti, Venezuela, and El Salvador. Within the jihadist category, the GTTAC includes attacks carried out by Al-Qaeda, ISIS, their affiliates, and local groups influenced by Salafi-jihadist ideology. Since 2022, the GTTAC has documented a rising number of jihadist attacks. These accounted for 39.4 percent of all recorded terrorist incidents in 2021, 36.7 percent in 2022, 41.3 percent in 2023, and 40.3 percent in 2024.
Figure 1: Total Terrorist Incidents and Religious-Jihadist Terrorist Incidents (2021–2024)
The persistence and proportion of jihadist attacks over consecutive years, as illustrated in Figure 1, indicate the enduring resilience of jihadist groups. Several structural and geopolitical factors contribute to this sustained threat. The transnational spread and financial support of Salafi-jihadist ideology—particularly through funding from certain Gulf States—has facilitated the growth of extremist movements in regions such as Africa and Asia. Additionally, political instability following military coups in Mali, Burkina Faso, and Niger has created power vacuums that groups such as al-Qaeda’s JNIM and ISIS–Greater Sahara rapidly exploited. Compounding these issues are chronic deficits in state capacity, including limited government resources, pervasive corruption, and porous borders, all of which undermine effective governance and provide fertile ground for jihadist entrenchment and expansion.
An additional key indicator of jihadist group activity is the number of casualties they have inflicted. As depicted in Figure 2, ISIS-Core—primarily active in Syria and Iraq—was responsible for 17,924 deaths and injuries between 2018 and 2024. This was followed by al-Qaeda’s affiliate, al-Shabaab, which accounted for 16,318 casualties during the same period. The top eight most lethal groups during this timeframe also include other ISIS and al-Qaeda affiliates, underscoring the continued operational capacity and persistent threat posed by these transnational jihadist networks.
Furthermore, these organizations are among the most frequent users of improvised explosive devices (IEDs), rockets, mortars, and small arms. An analysis conducted by the GTTAC of explosive weapon usage by Hamas, Hezbollah, ISIS-Core, and al-Shabaab from 2018 to 2024 reveals that ISIS-Core was particularly active in deploying grenades and landmines. The group carried out 177 grenade attacks, resulting in 356 fatalities, and 239 landmine-related incidents, which caused 530 deaths. Al-Shabaab followed closely, with 131 grenade attacks that led to 396 fatalities. In terms of mortar attacks, al-Shabaab was the most active, conducting 138 operations that resulted in 438 deaths.
Figure 2: Top Eight Groups with the Most Casualties (Killed and Wounded) (2018-2024)
Jihadist groups also remain the primary perpetrators of suicide bombing attacks, as illustrated in Figure 3. Between 2018 and 2024, al-Shabaab carried out 170 suicide attacks, resulting in 1,764 fatalities. ISIS-Core followed, causing 970 deaths through such operations. The list of major actors also includes the Taliban, which deployed suicide bombers until its takeover in 2021, along with various other affiliates of al-Qaeda and ISIS. Notably, ISIS’s affiliate in Afghanistan, the Islamic State Khorasan Province (ISIS-K), conducted 77 suicide bombings during this period but was responsible for the highest number of fatalities, with 1,952 deaths—underscoring the group’s high lethality per attack and strategic emphasis on mass-casualty operations.
Figure 3: Top 10 Groups with the Highest Number of Suicide Bombing Attacks (2018–2024)
Iran-backed Terror Groups
Iran’s involvement in regional terrorism and destabilizing activities is rooted in its strategic doctrines of “extended deterrence” and “forward defense,” which aim to counter threats beyond its borders by projecting influence through asymmetric means. Central to this approach is the concept of velayet-e faqih, which grants the Supreme Leader overarching religious and political authority, including a perceived obligation of obedience that extends to ideological allies and proxy groups outside Iran. This doctrine is grounded in Twelver Shiism, the dominant branch of Shi’a Islam in Iran, which emphasizes clerical authority and the role of religious leaders in guiding the political order—an interpretation that has shaped the Islamic Republic’s revolutionary ideology. At the core of this strategy is the so-called “Axis of Resistance” (mehvar-e moqavemat), a network of state and non-state actors aligned with Iran, through which Tehran seeks to deter adversaries, project influence, and defend its interests across the region.
Through this network of proxies and non-state actors—such as Hezbollah, various Iraqi Shi’a militias, and the Houthis in Yemen—Iran exerts influence across the Middle East while minimizing direct confrontation. This strategy also involves systematic interference in the internal affairs of neighboring states, exploiting sectarian divisions and fragile political institutions to shape outcomes in its favor. Beyond its traditional areas of influence, Iran has also sought to expand its reach into countries such as Turkiye, utilizing ideological networks, intelligence operations, and the cultivation of covert structures. A notable example is the formation of the group Salam Tawhid Quds Force, which was the subject of a Turkish police investigation in the early 2010s due to its suspected links to Iranian intelligence and its involvement in espionage and subversive activities.
Iran’s sponsorship of terrorism is characterized by strategic pragmatism rather than strict ideological alignment, as the regime supports both Sunni and Shi’a groups based primarily on shared geopolitical objectives. Tehran has consistently provided financial, logistical, and operational support to any group that aligns with its broader goal of countering the United States, Israel, and their regional allies. This pragmatic approach explains Iran’s historical sheltering of al-Qaeda operatives, including the group’s second-in-command, as well as its support for the Taliban during its insurgency against U.S. forces in Afghanistan. Similarly, Iran has extended material and logistical assistance to a range of Palestinian factions—including both Sunni and Shi’a elements—that engage in armed resistance against Israel. At the same time, Tehran has taken a hostile stance toward Sunni extremist groups that target Shi’a communities across the Middle East, viewing them as direct threats to its regional influence and sectarian interests. Iran’s long-term investment in proxy groups and militant networks was starkly demonstrated during the Hamas-led attacks on Israel on October 7, 2023, which revealed the depth of Iranian backing and the strategic patience with which the regime builds and maintains its regional alliances.
According to GTTAC’s group categorization, Iran-backed terrorist activity encompasses both Shi’a militant organizations and various Palestinian factions, illustrating Tehran’s strategic use of a diverse network of proxies to project influence and further its geopolitical objectives across the region. As depicted in Figure 4, the number of terrorist attacks attributed to Iran-backed actors reached a significant peak in 2024. In 2021, GTTAC recorded 364 such attacks, a figure that remained relatively stable through 2022. However, there was a dramatic escalation following the Hamas-led October 7, 2023, attacks, which marked a turning point in the operational tempo of Iran-aligned groups. Under strategic direction from Tehran, these groups launched coordinated attacks targeting U.S. and Israeli interests across the Middle East, contributing to a sharp increase to 936 attacks in 2023. This trend intensified further in 2024, culminating in 2,266 recorded incidents. The share of Iran-backed attacks relative to global terrorist activity also rose substantially, increasing from 4 percent in both 2021 and 2022 to 12 percent in 2023 and ultimately making up 26 percent of all recorded attacks in 2024. These figures highlight Iran’s expanding role in orchestrating and sustaining regional militancy through proxy warfare.
Figure 4: Number of Terrorist Incidents Attributed to Iran’s Backing (2021–2024)
Figure 5 presents the distribution of terrorist attacks carried out by Iran-backed groups. In 2024, Hezbollah emerged as the most active among these groups, with 1,409 recorded attacks, reflecting a significant escalation in its operational tempo. This was followed by the Houthi movement, also known as Ansar Allah, which was responsible for 391 attacks during the same period. Hamas also demonstrated a marked increase in its activities across 2023 and 2024, coinciding with the broader surge in Iran-aligned militancy. A particularly noteworthy development is the emergence of the group known as the Islamic Resistance in Iraq, which gained prominence following the Hamas-led October 7 attacks. Despite its recent formation, the group conducted 181 attacks across various Middle Eastern countries in 2024, signaling its rapid integration into Iran’s proxy network.
Figure 5: The Number of Incidents by Iran-backed terror groups (2018-2024)
In addition to the alarming number of terrorist attacks perpetrated by Iran-backed groups, these actors are also responsible for the highest volume of rocket and missile attacks, indicating a level of sophistication and access to military-grade weaponry that strongly suggests state sponsorship. Between 2018 and 2024, Hezbollah and Hamas were the primary perpetrators of rocket attacks, with Hezbollah conducting 953 such incidents resulting in 46 fatalities, and Hamas launching 499 attacks that caused 20 deaths. Missile attacks during the same period totaled 315 incidents, primarily attributed to Hezbollah, and resulted in 60 fatalities. The increasing use of unmanned aerial vehicles (UAVs) represents a notable evolution in the operational capabilities of these groups. Iran-backed actors have emerged as dominant users of UAVs in the region, reflecting both technological transfer from the Iranian state and a strategic shift toward more advanced forms of asymmetric warfare.
Despite the significant number of terrorist attacks by Iran-backed groups over this data set, recent Israeli military operations have significantly degraded the capabilities of Hezbollah, Hamas, and the IRGC-Quds Force through targeted strikes on leadership, weapons infrastructure, and logistics networks. These setbacks raise important questions about the long-term viability of Iran-backed groups as the core of a potential ‘fifth wave’ of terrorism. While Iran may adapt by strengthening remaining proxies or cultivating new ones, continued pressure could undermine the strategic coherence of its transnational militant network.
Other Threats for the Fifth Wave of Terrorism
The debates on the fifth wave of terrorism also have listed cyberterrorism, nuclear terrorism, and right-wing extremism.
Cyberterrorism
Cyberattacks have been conducted by a range of actors, including hacktivists, criminal organizations, state entities, and terrorist groups. Among these, the first three—hacktivists, criminals, and states—are the most active, and their operations have elevated cyberattacks to a top priority on global security agendas. In contrast, cyberterrorism is only minimally represented in terrorism databases, largely due to definitional ambiguities and methodological challenges in classification and data collection.
Cyberterrorism can be classified based on methods, targets, outcomes, perpetrators, and motivations. Common techniques include malware, viruses, and Trojan horses, often delivered via infected devices or software. While such attacks may qualify as cyberterrorism, social engineering tactics like phishing do not necessarily meet this definition. Typical targets include critical infrastructure—military sites, government offices, power stations, and commercial centers. Attacks causing physical harm, such as explosions, are generally considered cyberterrorism, whereas data theft or financial crimes are not.
Perpetrators range from non-state actors, including lone hackers, extremist groups (e.g., far-right or Salafi-jihadists), and ideologically motivated individuals. Not all cyber operations by terrorist groups constitute cyberterrorism; activities like propaganda or recruitment fall under information warfare. Motivations are often political, religious, or social, aiming to coerce governments or alter policies.
The literature distinguishes between cyber-enabled terrorism and direct cyberterrorism targeting information and communication systems. Cyber-enabled terrorism involves the use of digital tools to support traditional terrorist activities, such as propaganda, recruitment, fundraising, and operational coordination. These actions exploit cyberspace but do not constitute attacks on digital infrastructure.
In contrast, direct cyberterrorism refers to deliberate attacks on information and communication systems themselves. Such operations target critical infrastructure—government networks, financial systems, energy grids—with the intent to cause disruption, fear, or economic harm. In this form, cyberspace becomes the primary domain of attack rather than a supporting tool.
It is essential to acknowledge that, while cyber threats remain a top global security concern, the capacity of terrorist groups and ongoing definitional challenges will likely limit the extent to which theoretical security frameworks account for cyberterrorism as a significant threat.
Nuclear Terrorism
Nuclear terrorism represents a potential candidate for the theorized fifth wave of terrorism, reflecting growing concerns about the use of weapons of mass destruction (WMDs) by non-state actors. One of the enduring consequences of the September 11, 2001 terrorist attacks was the intensified discourse surrounding the hypothetical scenario in which such attacks were carried out using nuclear materials—an outcome that would have been significantly more catastrophic and deadly. For years, both practitioners and scholars have engaged in extensive debates regarding the likelihood of terrorist groups employing WMDs, which broadly encompass nuclear, radiological, chemical, and biological weapons. These discussions continue to shape counterterrorism strategies and underscore the need for vigilance in monitoring and preventing WMD proliferation.
Scholars have explored scenarios in which terrorist organizations might gain access to nuclear materials through illicit networks involving nuclear smugglers, corrupt officials willing to overlook or facilitate trafficking, and complicit scientists who may be coerced or incentivized to collaborate. While it is a matter of considerable concern that terrorist groups have made multiple attempts to acquire or deploy nuclear weapons, it is notable that these efforts have thus far been unsuccessful. In contrast, the post–September 11 era has witnessed the confirmed use of chemical and biological weapons by non-state actors, underscoring the continued relevance of non-conventional threats despite the relative inaccessibility of nuclear capabilities.
Several critical factors constrain terrorist organizations from acquiring and using WMDs. Among these, organizational capabilities play a central role, as complex planning and coordination are required to execute WMD-related operations. Financial and logistical resources are also significant limitations, as WMD development and deployment demand substantial funding and infrastructure. Furthermore, access to specialized knowledge and skills, as well as the ability to acquire necessary materials and technology, present additional barriers. Even if materials are obtained, challenges in production, weaponization, and the development of reliable delivery mechanisms further hinder terrorist efforts. Finally, the absence or withdrawal of state sponsorship can severely restrict access to expertise, materials, and safe havens, making it even more difficult for non-state actors to pursue WMD ambitions.
Despite the persistent failure of terrorist groups to acquire and deploy nuclear weapons, the continued incidents of theft and smuggling involving small quantities of radioactive and nuclear materials ensure that the threat of nuclear terrorism remains a subject of concern. Nevertheless, given the significant technical, logistical, and organizational barriers associated with nuclear weaponization and delivery, it is unlikely that nuclear terrorism will emerge as the dominant threat characterizing the fifth wave of terrorism.
Right-wing Extremism
A sense of ethnic and national superiority has driven various extremist groups to mobilize under right-wing ideologies and movements. This emerging trend has fueled the rise of anti-immigrant and xenophobic sentiment across Europe, while in the United States, Canada, and Australia, it has been associated with misogynistic, neo-Nazi, anti-government, and white supremacist groups. Although the number of right-wing extremist attacks recorded in the GTTAC database remains significantly lower compared to jihadist or Iran-backed terrorist incidents, the operational characteristics of these groups place them among the most dangerous terrorist threats today.
Often leaderless and decentralized in structure, these individuals tend to act as lone offenders, having been self-radicalized—primarily through online far-right platforms—and driven by extremist ideologies. This absence of a formal hierarchy or traceable network complicates detection and prevention, thereby elevating the threat level associated with such actors.
Recent developments have shown that right-wing extremist groups are adopting tactics, naming conventions, and networking strategies similar to those used by jihadist organizations. For instance, one such group operates under the name The Base, a direct translation of al-Qaeda. These groups are increasingly transnational, forming global networks with training activities previously identified in locations such as Ukraine (prior to the war) and Thailand.
While Western governments have been largely effective in countering global jihadist terrorism and are well-prepared to respond to conventional threats, right-wing extremist attacks present a different kind of challenge due to their decentralized nature, ideological diversity, and growing presence in online spaces. Although these attacks occur less frequently, they are often highly unpredictable, difficult to detect in advance, and capable of causing disproportionate societal and political disruption—making them a critical issue on current security agendas.
Conclusion
In conclusion, the global community has not only operationally failed to prevent several major terrorist attacks over the past two decades—such as those in the United States and various European countries, as well as the recent October 7, 2023, Hamas-led attack on Israel—but has also struggled academically to accurately identify and anticipate evolving terrorism trends. As a result, scholarly and policy debates have centered on various categories of terrorist threats, including Salafi-jihadist organizations, Iran-backed militant groups, and right-wing extremist actors, alongside thematic concerns such as cyberterrorism and the potential for nuclear terrorism. These discussions often seek to determine which among them represents the most likely candidate for the so-called “fifth wave” of terrorism.
Data from the GTTAC database indicates that Salafi-jihadist groups—particularly those affiliated with al-Qaeda and ISIS—remain the most operationally active, especially across Asia, the Middle East, and Africa, where they are responsible for thousands of fatalities annually. While the Western world has often perceived these threats as geographically contained, the growing capabilities and transnational ambitions of such groups pose a rising threat to global security, including that of Western nations themselves.
Simultaneously, the GTTAC data shows an increasing number of attacks perpetrated by Iran-backed groups. The October 7 Hamas attack has served as a significant turning point, drawing heightened attention to the operational reach and strategic ambitions of Iran-aligned actors across the Middle East. However, the recent decimation of Hezbollah, Hamas, and IRGC-QF leadership and infrastructure raises questions about the long-term viability of Iran-backed groups as central actors in the evolving landscape of global terrorism.
Other potential drivers of the fifth wave of terrorism include cyberterrorism, nuclear terrorism, and right-wing extremism. Although terrorist organizations have so far lacked the capacity to conduct large-scale cyberattacks or acquire nuclear materials, the potential impact of such capabilities—should they be obtained—would be significant. However, the likelihood of these developments occurring in the near term remains low. In contrast, right-wing extremist violence, while geographically limited primarily to Western contexts, poses a significant and growing challenge due to its decentralized structure, lone-actor tactics, and the difficulty of early detection. Thus, while its scope may be narrower, its unpredictability and ideological resonance warrant ongoing scholarly and policy attention. Based on the current operational data and ideological trends, Salafi-jihadist groups remain the most likely drivers of the fifth wave of terrorism globally, particularly in non-Western regions, while right-wing extremism may represent a parallel but regionally concentrated wave within the West.
