Iraqi counter-terrorism forces stand guard in front of the US embassy in the capital Baghdad on January 2, 2020.

Global terrorism claimed less lives in 2018, but its economic and social impact remains widespread, according to the latest Global Terrorism Index (GTI) from the Institute for Economics and Peace (IEP).

"Although the intensity of terrorism has diminished, its breadth has not," the Australian-based think tank warned.

The total number of deaths from terrorism declined for the fourth consecutive year in 2018, falling by 15.2% on the year to 15,952 — a 53% reduction since its peak in 2014.

The primary driver of the reduction in deaths has been a fall in the intensity of conflict in the Middle East, and military successes against terrorist groups like ISIS and Boko Haram.

However, the report adds that terrorism remains a widespread problem and a major global threat — costing the global economy a conservative estimate of more than $34 billion in 2018.

"This is the second worst year on record for the number of countries suffering at least one death, and highlights the need for continued assertive international action to combat terrorism," the report said.

"The international community has been very good at taking away the capabilities of terrorist groups to harm and commit their attacks, but the ideology, root cause and the grievances for international terrorism are still there," Serge Stroobants, director for MENA and Europe at IEP told CNBC's "Capital Connection."

"What we have seen over the past 20 years is, of course, acts of Western foreign policy and Western intervention have had an impact on the level of terrorism in different regions of the world," he added, as tensions soar in the Middle East and questions linger about America's military presence in Iraq and its broader strategy in the region.