• Weak and unstable states and corrupt or ineffective governments.
• Poverty and high unemployment, particularly among young men.
• Access to more lethal weaponry and increasing use of tactics like suicide bombings capable of killing scores of bystanders.
• A spike in sectarian tensions between Sunni and Shiite Muslims, where ancient grudges give rise to modern massacres.
• The increasing use of terrorism as a tactic in war.
“The distinction between the front line and home front has largely been erased as terrorism has become a growing feature of contemporary warfare,” said Brian Michael Jenkins, a senior adviser at the RAND Corp. and the founder of its counterterrorism program.
But Jenkins also cautioned that “terrorism” is notoriously difficult to define, and the increase in attacks does not necessarily mean the United States is “losing the war on terror.” He said it could just reflect a shift in strategy among Syrian rebels and Afghani radicals, for example.
Still, experts say the apparent increase in civilian casualties is alarming.
Gone are the days when terrorist groups like the Irish Republican Army or Italy’s Red Brigade would try to keep casualties low by issuing warnings, LaFree said.
“If you’re a terrorist group now and you want to get your message out,” he said, “the more people you kill, the more ‘successful’ you’ll be.”
Sectarian attacks -- such as the pitched battles between Sunni and Shiite Muslims in Iraq, Syria and Pakistan -- tend to be disproportionately deadly, said Martha Crenshaw, an expert at Stanford University and a START board member.
“Sadly, it seems to be increasingly acceptable in certain belief systems to kill as many members of the other religious community as possible,” she said. “Moral restraints seem to be eroding.”
Bombings and explosions were used in 58 percent of terrorist attacks in 2012, but it wasn’t always this way. In fact, START’s data also show a dramatic global shift in terrorist tactics and hot spots.
In the 1970s, most attacks were committed with guns and occurred in Western Europe. In the 1980s, Latin America saw the most terrorist acts. Beginning with the 1990s, South Asia, North Africa and the Middle East has seen steadily rising number of attacks, a trend that has accelerated in recent years.
Although terrorism touched 85 countries last year, just three -- Pakistan, Iraq and Afghanistan -- suffered more than half of 2012’s attacks (55 percent) and fatalities (62 percent).
In January, Sunni suicide bombers attacked scores of Shiite pilgrims in Iraq, killing at least 73. In February, a car bomb outside a café in Mogadishu, Somalia, left 15 dead. In March, a bombing in Thailand killed 14 and injured 340 in a commercial district.
Just eight private U.S. citizens died in attacks outside the United States in 2012, all in Afghanistan, according to the State Department. In the United States, seven people died in 11 terrorist attacks last year, six of them in a shooting at a Sikh temple in Oak Creek, Wis.
Despite the death of Osama bin Laden and capture of other key al Qaeda leaders, the group has exported its brand of terrorism to other militant Muslims, according to START and other counterterrorism experts.
“We’ve had success in stopping al Qaeda central,” LaFree said. “But we have been unsuccessful in stopping the message.”
Afghanistan’s Taliban was by far the deadliest group in 2012, when it launched 525 attacks that killed 1,842 people.