Despite population ageing in some societies, including in East Asia, the world on the whole is getting younger. Yet, many young people lack the basic skills to make the most of what the world has to offer.
There are today 250 million children of primary school age who cannot read or write, and some 71 million teenagers who are out of secondary school. A lost generation is in the making.
We must get them into school and make sure they get the skills they need. We need a revolution today for skills, for quality education, to provide young people with the tools they need to lead decent lives, to get decent jobs. If we fail, we undermine the foundations for stability and peace, for sustainable development.
The situation is dangerous. In the Arab world, 28 million young people, aged between 15 and 25, have not completed primary schooling. This represents one-tenth of the region's population. In sub-Saharan Africa, 56 million youths have not completed primary schooling, about a third of the total.
One young person in eight is unemployed in the world today. One in four works for just over a dollar a day. Girls are hit hardest everywhere. The poor, in cities and rural areas, face the steepest obstacles. All of this fuels adult illiteracy - there are 775 million women and men today who cannot read or write.
With the demographic "youth bulge", the problem is not just that these young people are marginalised from society - it goes deeper. If we fail to act, youth without skills will increasingly shape our societies. The knowledge societies we need for the 21st century must build on skills.
The price that societies pay for raising children without basic skills is unacceptable. It is a violation of individual dignity and human rights. It impedes business and economic growth. It also tills the soil of unrest.
Unesco's newly released Education for All Global Monitoring Report on "Youth and skills: Putting education to work" shines the spotlight on this crisis in the making.
Governments must do far more to ensure every girl and boy gets the learning they need. The business world must also step up. We need to build new partnerships between the public and private sector because we are all in this together.
This requires additional financing. Fixing the skills deficit is a way to fix the future. We calculate that countries need US$16 billion every year to ensure all children enter primary school by 2015 and an additional US$8 billion to ensure universal lower secondary school enrolment.
That sounds like a lot. Viewed from the angle of the world's military spending, estimated in 2011 at US$1.74 trillion - it isn't. Education is simply the best investment in the societies and economies we want and need.
Irina Bokova is director general of Unesco