NEW YORK—The risk of a major terrorism attack inthe U.S. is lower for 2013 than it was for 2012 due tochanges in the global terrorism landscape including the death ofOsama bin Laden and one of his deputies, according to RiskManagement Solutions.

Gordon Woo, RMS catastrophist, said at a conference held herelast week that bin Laden’s death and the removal of deputy AbuYahya Libi—who RMS called a “conduit” between Pakistan’s militarycommanders and Al-Qaeda operatives in Iraq, Yemen, and othercountries located to its west—have interrupted the planning oflarge-scale operations. Woo added that the Arab Spring has alsotemporarily affected al Qaeda’s ideological pull.

These factors have reduced the likelihood ofthe U.S. suffering a “macro attack,” defined by RMS aspremeditated events that cause losses in excess of $1 billion, morethan 50 casualties, 250 injuries, and/or massive symbolic damage,said Woo.

As a result of the lower risk for a macro attack, RMS’ 11thannual U.S. Probabilistic Terrorism Model (PTM) indicates that thepredictedU.S. annual insured loss from terrorism is about 20percent lower for 2013 than for 2012.

Woo says, “Within the standard risk outlook for 2013, thereis a reduction of 19 percent in both property and workerscomp AAL [annual aggregate limit]. For the reduced riskoutlook, the property AAL falls from $2.21 billion in 2012 to$1.64 billion in 2013.”

There have been a total of approximately 30 attemptedmacro-terror plots that led to a conviction for terrorist offensesin the past decade, including a recent plot in which five menlinked to an anarchist group were charged on May 5 with plotting tobomb a bridge in Ohio.

As for the future risk of macro attacks, Woo said forces may bewaiting for the opportunity to gain access to a chemical,biological, radiological, or nuclear (CBRN) arsenal; for a pass ata significant geographical region; or to attack on a culturallysignificant date.