“The biggest displacement crisis of all time.” That is what António Guterres, the United Nations High Commissioner for Refugees, this week called the 6 million Syrian refugees – a quarter of the country’s people – uprooted from their homes.

This may be the biggest impact of the Syrian civil war, says Anthony Cordesman of the Center for Strategic and International Studies in Washington DC. That many people with no real home, income or access to adequate food, education and medical services leaves a lasting legacy of hatred and insecurity, and cripples education, agriculture, healthcare and investment in development for well over a decade, he says. The effects will be felt throughout the entire region.

So far, 4.25 million men, women and children have moved somewhere safer within Syria since the conflict began in 2011. But 2 million more have fled, mainly to Lebanon, Jordan, Turkey and Iraq.

Numbers are still rising, and two-thirds of the refugees are moving to towns – not refugee camps – where they are harder to track, and compete with locals for already scarce resources and jobs.

“Syria is haemorrhaging women, children and men who cross borders often with little more than the clothes on their backs,” said the UN High Commission for Refugees (UNHCR) in a statement yesterday. It has a detailed plan for caring for refugees outside Syria, and in June asked world governments for $3 billion to pay for it. It got $1.2 billion. On Wednesday, the host countries’ foreign ministers and Guterrez called for more help.

Water, water… nowhere
The influx has swollen Jordan’s population by 10 per cent. The country expects a million refugees by the end of the year, a third in camps, yet barely has enough water for its own people. “Public water supply systems are under severe stress,” says the UNHCR. “Tensions between refugees and Jordanians are rising.” The UN World Food Programme (WFP) is giving refugees vouchers to buy food on local markets, pumping $120 million into the host countries’ economies – which has helped to improve relations.

The Al Za’atri refugee camp near the Syrian border is now Jordan’s fourth largest city, with a population of 120,000. It stopped taking new arrivals last week. Trucking in 3.4 million litres of water daily is too expensive to continue, says the UNHCR, and lower sanitation standards may be the only option.

The camp is being reorganised to fight a crime wave. Refugees are digging toilets to avoid using dark latrine blocks at night, because budget shortfalls and rampant theft quashed plans for solar lighting.

Jordan opened a new camp for 80,000 this week, west of the Azraq oasis which supplies 25 per cent of Jordan’s drinking water. The oasis is already pumping at more than twice the highest sustainable rate, risking permanent damage to the aquifer. Warnings were sounded more than a year ago that the extra strain of more refugees could be disastrous. Jordan is trying to pull in extra sources of water to ease the strain.

Disease spread
Hepatitis, tuberculosis (TB), lung and gut infections are spreading in camps, as is leishmaniasis, a potentially disfiguring skin parasite spread by desert sandflies.

The mass migration could change the disease landscape, warn public health experts. Jordan has called off plans to eliminate TB this year. The disease was almost gone from the country. The parasitic disease schistosomiasis was largely eliminated from Syria’s neighbours, but refugees could once more spread it in the region. In 2012, Jordan had among the first cases of the lethal MERS virus; virologists fear it is present at low levels in the region and could get out of control among crowded, weakened refugees.

In camps, at least, children can be vaccinated: 98 per cent have got booster shots for measles and polio. But within Syria, public health services have broken down. A measles epidemic swept northern Syria in June, as Médecins sans Frontières struggled to supply vaccine. Such outbreaks delay the whole region’s efforts to eliminate that virus, as the Americas have done.

Animal vaccination has also stopped in Syria, says the UN Food and Agriculture Organization (FAO), yet desperate farmers are selling their livestock outside the country. Cases of rabies, bovine TB and severe afflictions such as lumpy skin disease have already spread from Syria to neighbouring countries, in what the FAO calls “a serious regional animal-health problem waiting to explode”.

The food situation is no less critical. Ironically, the rains returned this year after five years of drought that are thought to have helped spark Syria’s uprising. But fighting and bombs dropped on irrigation facilities and crop stores have halved wheat production and doubled prices, says the FAO. In the face of unemployment and steep inflation, refugees and Syria’s poor cannot buy food. Four million face hunger. The WFP cannot feed them all.

Military strikes against Syria in response to the chemical weapons released in August, may only accelerate the flood of refugees and worsen the overall situation.