Ask 10 people you know to identify the thunderclap that started World War II. The answer would vary, depending on the perceptiveness of the person being asked and their geographic location. Former British Prime Minister Winston Churchill was warning anyone who would listen about Nazism long before Hitler's rise to power in the early 1930s. America, by contrast, was only fully pulled into the war when Japan attacked Pearl Harbor in December 1941.
Likewise, most people would probably say that the Cold War started in earnest around the time of the Cuban Missile Crisis in 1962. They likely wouldn't consider a much more discreet but equally significant event: the defection, on September 5, 1945, of Igor Gouzenko, a cipher clerk at the Soviet Embassy in Ottawa, Canada, who fled his post carrying 109 documents detailing Soviet infiltration of the West.
Did anyone who was alive in 1945 believe that the Cold War had already started? Well, history has effectively and retroactively determined that it had indeed begun by that point. The same could be of the events underpinning the multitude of dire warnings from Churchill long before history ever considered those events significant.
So has World War III already started? And if it has, does it fit the description offered by the pope?
A Third World War would be highly decentralized, complex, covert and tactically diverse, and it would transcend the state-vs.-state paradigm. Wars currently underway in the world are either ideological in a purely religious sense, or strictly economic with a view toward maximizing profits (as opposed to peddling communism or capitalism as ideologies). Both of these phenomena are occurring simultaneously.
The Islamic State terrorists in Syria and Iraq, Boko Haram in Nigeria, Uighur extremists in China, and various other Islamic extremist groups throughout Africa, Asia and the Middle East -- with recruitment efforts that reach into developed Western nations -- are belligerents in one type of conflict: religio-ideological. They're essentially guerrillas of widely varying backgrounds, pulled from all over the world to fight with groups largely lacking in hierarchy and organization.
The second set of belligerents is comprised of nation-states, engaged in similarly decentralized economic warfare that isn't strictly limited to their own geographic boundaries or any politico-ideological agenda. The emphasis on economics rather than on homeland perimeter defense or the defense of political ideology is what makes the current set of nation-state conflicts different from World War II and the Cold War.
China, for example, has been gobbling up resources in South American and African countries without firing a shot. It's this kind of warfare that explains why nation-states engage in economic intelligence activities from within their foreign embassies -- a fact that former NSA contractor Edward Snowden apparently found shocking enough to disclose publicly. The disclosure of such top-secret intelligence can cause grave harm to national interests by hampering a country's competitiveness. Whether an economic disadvantage ultimately translates into a national-security detriment is a matter of debate. But it's not a stretch to imagine that a country taking an economic hit would experience an overall decline in resources, including a decline in national security.
Both types of contemporary warfare -- religio-ideological and nation-state economic -- feature new tactics that we haven't seen before, most of which involve the leveraging of new technology for the purpose of psychological warfare. Two common examples are using social-media platforms to distribute information and propaganda, and using cyberattacks to gain publicity or evoke public fear.
Arguably, there are currently enough conflicts around the globe in both categories to retroactively constitute flashpoints in WWIII. What remains to be seen is whether the religio-ideological "hot" wars might somehow merge with the nation-state economic "cold" wars, taking us past a point of no return and toward the worst possible outcome.
The ideal scenario would be for the nation-state conflicts to cool and take a back seat until its players can figure out how to get a grip on religio-ideological warfare -- the solutions to which have continued to elude them all. Otherwise, religio-ideological conflict may go down in history as the lone fuse that ignited WWIII while the superpowers were all collectively distracted.