The Italian Prime Minister Matteo Renzi has threatened the EU with a "plan B" on immigration if Italy's neighbours don't share more of the burden. That is not happening. On the contrary, France is forcing would-be migrants back into Italy, in the Riviera border town of Ventimiglia. But it's not just Europe that's facing an unprecedented wave. This summer, the planet faces the greatest uprooting of populations since World War Two.
