More than a million people fleeing war, persecution and poverty in the Middle East and Africa crossed the Mediterranean to Europe in 2015. The number of people who died making the perilous crossing in often unseaworthy boats and dinghies was at least 3,770. So far this year, more than 76,000 people have reached Europe by sea — nearly 2,000 per day — and 409 of them have died trying, most drowning in the cold, rough waters. The number of arrivals in the first six weeks of 2016 is nearly 10 times as many as the same period last year.

The influx of refugees has plunged the European Union into what some see as the most serious crisis in its history. In response, Nato has ordered three warships to sail immediately to the Aegean Sea to help end the deadly smuggling of asylum-seekers across the sea from Turkey to Greece. However, there is uncertainty about the precise actions they would be performing, including whether they would take part in operations to rescue drowning people.

The record movement of people into Europe is a symptom of a record level of disruption around the globe, with numbers of refugees and internally displaced people far surpassing 60 million, according to the UN refugee agency. The war in Syria is only one among many causes, including Ebola and Boko Haram in west Africa, an earthquake in Nepal, conflicts in Libya, Yemen, South Sudan, Central African Republic and Afghanistan and Iraq.

Greece, with thousands of kilometres of coastline and islands very near the Turkish coast, is the main gateway into Europe for those fleeing the Middle East, while Italy, Malta and Spain are the main destinations for those making the journey from north and west Africa.