Since 1990, there have been a number of developments in terrorism and political violence that are likely to be significant in the longer term.

Terrorism and insurgency
The practice of employing regime termination as a major response to terrorism produced a complex reaction that effectively mixes terrorism and insurgency. This evolved in Afghanistan and Iraq into a form of warfare that may be concentrated in the two countries concerned but has a much wider impact, not least in Pakistan and in terms of support for the al-Qa’ida movement and its associates.

Internationalism (globalization)
In the first six years of the war on terror, the al-Qa’ida movement and its loose affiliates were able to carry out attacks in Egypt, Indonesia, Jordan, Kenya, Morocco, Pakistan, Saudi Arabia, Spain Tunisia, Turkey, the UK, Yemen.

Suicide terrorism
Though this is not new, the intensity of the attacks in many countries, and the willingness of so many to engage in martyrdom is novel. Suicide attacks are intrinsically more difficult to counter as an aspect of any form of political violence. Moreover, while most of the relatively rare incidents of suicide attacks until 2001 were by people with deep political or ethnic motives, the more recent trend is for suicide attacks to draw on religious motivation, especially within Islam, and for there to be substantial increase in the numbers of motivated individuals who embrace an eschatological dimension to their aspirations.

Speed of learning
Most paramilitary groups in the past have been relatively conservative in their operations, tending to stay with methods that they have developed and have become experienced in using. The intense environments of the insurgencies in Afghanistan and especially Iraq forced paramilitary groups to learn fast in order to survive and thrive. There is abundant evidence that these learning environments have combines with the internationalization of terrorism to allow the far more rapid spread of tactics than in the past – advanced fusing for improvised explosive devices and the production of explosively formed anti-armour projectiles being just two examples.

Media developments
Regional satellite TV news channels, the use of the internet and mobile phones have all increased the ability of paramilitary groups to promote their causes.

Economic targeting
The development of sophisticated economic targeting strategies by groups such as the Provisional IRA and insurgents in Iraq has provided a new avenue of influence. Given the numerous nodes of power and economic activity in urban/industrialized societies, it is probable that this development is still in its early stages.

Mass casualty attacks and weapons of mass destruction

Although there has been no single instance of the large-scale of nuclear, chemical biological or radiological weapons, the increased use of mass casualty attacks has raised fears that weapons of mass destruction will ultimately be used by terrorist organizations. While there is clearly a risk, it remains the case that conventional forms of destruction can readily lead to casualties on a very substantial scale, as in the 9/11 attacks.

Source:
Rogers, Paul. "Terrorism" in Williams, Paul D. Security Studies: an Introduction. pp.232-233.