Of all the millions of words expended in the global media on this year's rash of youth-led revolts across the globe, none are more relevant than those penned by Alex Andreou, a Greek-born blogger who now lives in Britain. "You have run out of ideas," he wrote in June, echoing the message of Greek protesters to their country's political and economic elites. "Wherever in the world you are, that statement applies."

Andreou was writing as the occupation of Syntagma Square – Athens's central plaza – was entering its fourth week, and he went on to summarise what had moved Greek demonstrators to take to the streets: a refusal to suffer any further in order to make the rich even richer, a withdrawal of consent and trust from the politicians governing in their name, and finally that simplest and most devastating of censures from one generation to the next. Those in power, he said, were devoid of fresh thinking, and this is why "the protests in Greece affect all of you directly".

When the dust has settled on 2011 perhaps the aspect of it that will prove most striking to historians is that in a period where so many old certainties dissolved, from the stability of dictatorships in the Middle East to the sturdiness of the neoliberal economic framework in Europe, America and beyond, those with their hands on the levers of formal power had so few ideas to offer. From Arab autocrats to eurozone finance ministers, paucity of original thought has prevailed at the top and the prescription has always been more of the same: reheated rhetoric and stencil-cut solutions, all worn lifeless with weary familiarity.

Little wonder then that from Santiago to Sana'a, something else has arisen to fill the void – and that those still rooted in the old models of thinking find themselves lacking the linguistic tools necessary to even describe the phenomenon, never mind understand it.

A "global temper tantrum" is the most historian and empire cheerleader-in-chief Niall Ferguson could muster in his effort to characterise this year's developments, which have seen hundreds of thousands in north Africa, led by the young, braving bullets to topple entrenched regimes. Meanwhile in southern Europe, South America, Wisconsin and London, city centres have been occupied and youths have mobilised, challenging existing power structures and fighting – with messy, uneven consequences – to articulate an alternative.

We are witnessing, says Priyamvada Gopal, an English professor at Cambridge, the "momentary transformation of anger from a dirty word into the very currency of political exchange".

Each of these struggles has been specific to local contexts but they share more than just the imagery of occupied squares, tents and teargas. They are bound together by a common sense of disenfranchisement and the belief that the participants have it in them to create a new reality – and that at the moment, largely inspired by the Arab spring and the global economic meltdown, a window of opportunity to do so is open.

"The repression is brutal … and the teargas stronger than ever," says Camila Vallejo, president of the Chilean University student union which has brought 100,000 students on to the streets and taken control of 300 schools in an attempt to rebuild the country's education system from scratch – holding mass kissathons and Michael Jackson dance routines in the process. "We have been protesting not about reform, but about wholesale restructuring … if we don't have real change now, it's not going to happen."

The scope of her ambition echoes that found in Syntagma Square, where opposition to an EU/IMF bailout and its accompanying austerity measures has morphed into a broader critique of social injustice. "We are ordinary people, we are like you," reads the mission statement of the Real Democracy website – the online hub of the Syntagma protests – before going on to explore the alienation many Greeks feel from the organs of the state. "Without us none of this would exist, because we move the world … I am outraged. I think I can change it."

It's easy to overstate the linkages; those joining the anti-government uprising in the Syrian town of Hama and los indignados of Barcelona and Madrid are striving to confront very different enemies and are facing wildly dissimilar levels of repression as a result. But connections are apparent, not least in the protesters' rejection of the old terms of debate and a commitment to build something else in response on the streets – a commitment most visible in Cairo's Tahrir Square, where protesters congregated not only to face down the regime but also to prove that an alternative was feasible; the chant ahum ahum ahum, al masryeen ahum ('here, here, here, the Egyptians are here) was a snub to Hosni Mubarak, but also a reminder that the contours of society were being reimagined from the ground upwards.

Elites have yet to grasp that hunger for meaningful grassroots change and the desire to reclaim agency over a future that appears depressingly predetermined, be it under the crony capitalism and police brutality of Middle Eastern despots or the more sanitised platter of unemployment and austerity being handed down by governments in the west. Those on the other side of the divide have been unable to keep pace with the rapid shift in thinking; in his analysis, Ferguson adopts the kind of paternalistic tone that came easily to Mubarak as the octogenarian gently chided Egypt's youth for daring to question his authority, or to the unelected rating agency chiefs who condemn whole nations to poverty with a sad shake of the head and a well-intentioned finger-wag against spending profligacy.

"Historically in any country and in any context it's young people who are at the core of protests," says Gopal. "But at this moment in history we're seeing a shared sense of deprivation among the young, a shared sense of there being a democracy deficit across the world. In all these places neoliberal economic policies have intensified their hold and affected young people most directly, young people looking for employment, study, prospects. I think it has cut young people to the bone, and they're confronting it directly."

Two other common motifs run through this year's rebellions. First has been the collapse in authority of traditional institutions; from Mubarak's cult of personality to the seemingly incessant scandals engulfing Britain's arbiters of political, financial and cultural control – bankers, MPs, and the Murdoch media empire. The crumpling is contagious, fuelling rebellions in the most unlikely of places.

"People are on the edge, you can't fool us anymore," says Avi Cohen, a 25-year-old drama student who has joined a 2,000-strong tent protest on Tel Aviv's exclusive Rothschild Avenue. The protesters say they are campaigning for social justice, leaving the question of Palestinian injustice off the table for now in an effort to build the broadest possible consensus.

Like many of his counterparts elsewhere, Rotem Tsbueri has lost faith in the official mechanisms of political reform. "We're not interested in changing ministers or governments, we want to change the way things are done. It's not about who's in the government, it's about the way they work and think."

The 15-M movement in Spain, which organised demonstrations in 58 cities earlier this year under the slogan "they don't represent us", embodies a similar yearning for a new political framework to arise. "We don't want to form a political party because it would destroy the horizontal nature of the movement," says Carlos Pederes, an IT worker who has been involved in the protests from the beginning. "[Plus] the system is rigged so that only the two big parties can win, so it would be pointless."

The second commonality has been the tools used to mobilise dissent. Although the role of online social media in the Arab uprisings has often been overstated, there can be no doubt that platforms such as Twitter and Facebook have enabled diverse groups to quickly garner broad support for acts of resistance – and that this means of communication has coloured the internal organisation of protest movements.

"One of the most unifying aspects between our own organisation and other movements around the world is that we're relatively non-hierarchical and decentralised," says Steve Taylor, a campaigner with UK Uncut.

"Today there may not be a single unifying ideology of change among global youth protests of the sort that united people in 1968, but there is a common ideology embedded within our shared model of organisation – no egos, no celebrities, no one telling anyone else what to do and no one willing to take orders – one that lends itself to online social media and has captured people's imaginations."

The bonds between 2011's islands of youth dissent remain limited. Although the root causes of anger may be similar, the levels of politicisation among those expressing that anger vary wildly; Gopal says she was struck by the diffuseness and lack of direction in the recent British riots, contrasting it with protests in the Arab world, where "a focus and self-awareness that comes from those countries' recent history of anti-colonial struggle has been transmitted from one generation to the next". But this year could still be remembered as one in which, after many decades of moribund political and economic realities, a new narrative began to form.

As Andreou points out, Nassim Nicholas Taleb, the philosopher who coined the term "Black Swan event" – denoting a hugely consequential event that is utterly unpredictable and can only be explained afterwards – was recently asked by Jeremy Paxman whether the violence on the streets of Athens fell into that category. He demurred – and said that the real Black Swan event was that more people weren't rioting elsewhere. Additional reporting by Jonathan Franklin in Santiago, Stephen Burgen in Barcelona and Harriet Sherwood in Tel Aviv

• This article was amended on 17 August 2011 to reinstate the word 'unlikely' into the following sentence: "The crumpling is contagious, fuelling rebellions in the most of places."