Keith Ellison, a Minnesota congressman, is worried about Ayan Hasan and her family. He wrote recently to the New York Times about his Somali constituent, a medical worker who supports her family back home.

Her mother, stepmother, six siblings and blind uncle depend on her remittances, the money she sends home monthly. Or would if the US government hadn’t blocked it. The money went to food, water, doctor visits, housing and education. If she couldn’t send money home, she worries, her 14-year-old brother might drop out of school and be recruited by extremists.

In Dublin, Cork and around Ireland there are countless Ayans: Maciejs from Poland, Marias from the Philippines, Esthers from Nigeria . . . Collectively they sent home last year some €1.8 billion in remittances – 1 per cent of Ireland’s GDP – money that often makes the difference for families between survival and the breadline.

It is the side of the immigrant story that is rarely talked of, one often involving huge personal sacrifice, divided families with one or more parents away for years, children growing up with grandparents, older people alone surviving on the money from abroad. Increasingly it is seen in the development world as a huge untapped resource.

The figures for remittances are huge – and economically significant to many developing countries. Total global remittances in 2014 reached €543 billion. This is more than double the worldwide official development aid (ODA) spend. India received €65 billion, China €60 billion, the Philippines €26 billion. And remittances to the developing world alone are expected to reach €410 billion in 2015, according to new figures from the World Bank.

The largest of Ireland’s migrant communities, the Poles, sent back €202 million last year, an average of around €2,000 a head, while, apparently, the 16,500-strong Nigerian community was by far the largest remitter, sending home a deeply questionable €366 million, close to a staggering €22,000 a head. (Can anyone explain?)

Soaring figures

And let’s not forget the flow the other way: our diaspora sent home some €750 million in 2014, half from the UK and close to a fifth from the US.

But it is in parts of the developing world where the contraction in remittances for similar reasons is sharpening the crisis facing many families like Ayan’s. Her problems and those of other Somalis are exacerbated by attempts by the US to curb money flows which they see as potentially falling into terrorist hands. In poverty- and violence-stricken Somalia at least a quarter of the country’s GDP consists of remittances – some €1.2 billion last year – and annual remittances significantly dwarf international aid. Remittances in Gambia, Lesotho, Liberia and Comoros equal about 20 per cent of GDP.

Slowest

The fall in the value of the rouble and curbs on migrants have meant that in 2014, remittances to Ukraine contracted by 27 per cent, to Uzbekistan by 16 per cent, Armenia 11 per cent and Tajikistan 8 per cent. The last-mentioned is the world’s most remittance-dependent country, with remittances representing 49 per cent of GDP in 2013. A fifth of Armenia’s annual GDP comes from emigrants abroad and its revenue from its diaspora in Russia halved in the last year.

The 2015 remittance growth rates are the slowest since the global financial crisis in 2008/09. The World Bank predicts that flows to Europe and Central Asia will decline by 12.7 per cent further in 2015 although globally they will rise by some 4 per cent with the upturn in the world economy.

The number of international migrants is expected to exceed 250 million in 2015, and their savings and remittances are expected to continue to grow. “Diaspora savings” attributed to migrants from developing countries were estimated at €464 billion in 2013, mostly held in the banks of states to which they have migrated. The bank argues that, properly marshalled, these could serve as an important capital resource for the developing world.

There is also an important challenge for the international community in reducing the prohibitive cost of transmitting money – the global average cost of sending $200 has come down in recent years to 8 per cent of the value of the transaction, but shows no sign of falling further. A tax by the banking industry of up to €40 billion a year on the poorest.