Numbered at 1.8 billion, the world is now home to the largest generation of young people aged 10 to 24 in its history. Having grown up in a digital era and more connected than ever before, younger generations are able to see the world's boundaries as more fluid, recognizing their shared interests and values with people around the globe.

Child-sex tourism is a particular kind of commercial sexual exploitation of children, interrelated with prostitution, pornography and human trafficking for sexual purposes. It occurs when someone travels to a place and, while there, sexually abuses a local child or young person.

Of all the developments we have read about in the Syrian tragedy, the rising tide of child labour is one of the more concerning. We've worked on the issue of child labour for two decades, interviewing hundreds of too-young workers and learning about the long-term challenges they will face without an education. These kids want to help ease the burden poverty for their families now, but it will cost the Syrian people even more in poverty in the years to come. If there are no income opportunities for refugee families, we won't break the cycle of child labour.

"Research shows the earlier and longer youth spend in the system, the worse the outcomes are," says Peter Leone, a professor at the University of Maryland who has studied juvenile justice measures around the world for more than 20 years. It costs approximately $100,000 a year to incarcerate one young person in Canada. If that individual becomes a hardened life-long criminal, the amount will exceed a staggering $2 million, according to a Boys and Girls Clubs of Canada.

As Canada's streets fill again with yellow buses, we're reminded how fortunate Canadians are in the educational opportunities available to our children -- opportunities that do not exist for millions of others. And while the world has made great progress on education over the last decade, there are alarming signs we're losing some of the gains we've made. When the Millennium Development Goals (MDGs) to end extreme poverty were launched in 2000, the United Nations recorded more than 196 million children and teens not attending school. The biggest barrier is poverty -- And for many children, schools are far from their homes, requiring much more in boarding costs.

Every day we witness the power of young people to transform their communities and the world. The potential lost when a child is handed an AK-47 instead of a schoolbook or soccer ball is one of the greatest tragedies imaginable. But as governments stop recruiting children, over the past year militias and terror groups like the Islamic State, or ISIS, in Iraq and Syria, and Boko Haram in Nigeria, have horrifyingly indoctrinated thousands more. And the way these militias use their children is changing in terrifying ways.