The attempted machete attack on the Louvre Museum in Paris on February 2 is indicative of the changing terrorism threat environment.

Attacks carried out by lone individuals targeting civilians with guns, knives and even trucks – as was the case in Nice and the Berlin Christmas market attacks – are on the rise in OECD countries. Seventy percent of all deaths from terrorism in the West since 2006 have been perpetrated by lone actors, according to the Global Terrorism Index.

This is in large part a result of significant improvements in counterterrorism and surveillance, which has increased the likelihood of complex plots being intercepted, explains Gordon Woo, catastrophist at RMS. The mass surveillance, which was made known to the public by NSA whistleblower Edward Snowden in 2013, has helped to foil a significant number of major plots.

This includes the 2006 liquid bomb plot, which could have surpassed 9/11 in impact if it had fallen through the cracks, thinks Woo. “Within the Five Eyes Alliance, all the major plots since 9/11 – those involving over half a dozen operatives – have been stopped. This would not have been possible without intensive surveillance.”

Because of high per capita spending on counterterrorism in many other countries, would-be attackers have followed the path of least resistance in their choice of weaponry and mode of attack, he explains. “Since 9/11, it’s become harder to get hold of fertilizer to make bombs, so terrorists have shifted attack mode from chemical energy through bombs and explosives to, for instance, kinetic energy stored up in moving vehicles. A 40-ton truck travelling at 30mph (as was the case in Berlin) can cause as much damage as a bomb.”

The property losses arising from lone actors with guns or knives, or marauding firearms attacks that focus on soft targets, are significantly less than those involving improvised explosive devices (IEDs). However, businesses are exposed in other ways. This includes the threat to their staff and potential business interruption losses.

In France, the GDP contribution from tourism fell by US$1.7 billion between 2014 and 2015 following the January 7, 2015 Charlie Hebdo shooting and November 2015 Paris attacks. “All the terrorism carriers and pools are trying to become more relevant and looking at what cover they can provide for business interruption or some kind of restriction on business because of damage to infrastructure,” explains Woo.

“Direct economic loss, such as from property damage, may be minor compared with the indirect economic drain from interruption to tourism and other businesses,” he continues. “Measures to improve resilience against indirect economic losses from terrorism require new insurance solutions.”

While smaller attacks focused on soft targets remain the most likely form of terrorism risk, the threat of a major, complex attack has not disappeared. Groups such as ISIL and AQAP (Al-Qaeda in the Arabian Peninsula) seek to inspire and radicalize lone attackers but maintain their goal of waging “spectaculars” against Western countries.

The return of experienced foreign fighters from Iraq and Syria could prove a significant challenge for security agencies and governments, noted the UK’s Pool Re in its 2017 terrorism outlook. It also anticipates ISIL’s so-called Caliphate will become more “virtual” as it continues to make use of the Internet and social media to influence and gain access to sympathetic individuals.