The migrant crisis will never end. It is part of the modern world

Sometimes, one fact goes a long way towards explaining a global crisis. Behind the rubber dinghies laden with desperate people washing up on European beaches and the refugee camps spread across the deserts of Jordan - or, for that matter, the plains of Chad – lies a remarkable figure.

The number of people driven from their homes by conflict worldwide has jumped by 40 per cent since 2013. You have to go back to the early 1990s - the era of the Rwandan genocide and the Yugoslav wars – to find a time when the ranks of the huddled masses rose so sharply in such a short period.

The raw data are as follows: in 2013, the global total of refugees (who have escaped across borders) and “internally displaced people” (who are fugitives within their own countries) stood at 33 million. By 2015, the number had climbed by 13 million to reach 46 million.

The immolation of Syria was the biggest cause, but on the other side of the world, two million people fled the path of Boko Haram’s pitiless offensive in Nigeria; another 2.2 million escaped civil war in South Sudan. In the terse phrase of the International Institute for Strategic Studies (IISS), which compiled the figures, this amounted to a “quantum leap in forced displacement”.

Today’s wars generally create far more refugees than previous conflicts. It may sound strange, but that is not necessarily bad news. After all, the biggest reason is simply that even the most volatile countries have also experienced rapid population growth.

Had civil war broken out in Syria in 1970, the refugee crisis would have been a fraction of today’s catastrophe. Back then, Syria had only six million people, compared with at least 20 million today.

If Boko Haram had swept across northern Nigeria in 1970, the Islamist gunmen would have been ravaging a country with barely one quarter of today’s population. The refugee camps across the border in Chad would have been tiny by our standards.

There are more refugees because there are more people – and, in turn, there are more people because the world has broadly succeeded in reducing infant mortality and raising life expectancy, even in the poorest countries.

Many of those improvements, incidentally, were driven by the aid programmes of the very European countries that now find themselves inundated with refugees. The EU and its members have spent huge sums on primary health care and childhood vaccination campaigns across Africa and the Middle East. The result is that more children live to become adults, the population rises – and so does the number of people who are vulnerable to becoming refugees if war breaks out.

The volume of migrants heading for Europe is not solely because of war and poverty. The affected countries also have many more people than in the past – partly because Europe did the right thing by, for example, eradicating smallpox and immunising children against polio.

All this means that our understanding of the “migration crisis” will need to change. The very word “crisis” is misleading for it implies a passing moment of danger that will eventually come to an end.