We have often mentioned here on Demography is Destiny countries that are growing, but are relying for that growth substantially (eg Switzerland; Scotland; Canada) or wholly (eg Russia – not that Russia is actually growing) upon immigration.  That is, many countries are relying to a large extent on immigration to make up for their declining birth rates and ultimately, declining work forces and greying populations. 
This is not a risk-free option of course. It is hard to integrate migrants into a host country, especially when there are large numbers of such migrants and they are from a very different culture and speak a different language.  And then, of course, there is the impact upon the “native” population of the host nation.  This has been highlighted in the UK, where 100,000 people signed a petition on the Downing Street website on the level of immigration and thus forced a debate in the floor of the House of Commons on the subject.  Sir Andrew Green, chairman of Migrationwatch UK, wrote in the Telegraph of his concerns with the UK’s immigration policies:

“It is now expected that the UK population will reach 70 million in 15 years time. Of the extra 7.7 million, 5 million will be the result of new immigrants and their children.

This is stunning. It implies building the equivalent of our eight largest cities outside the capital – Birmingham, Manchester, Liverpool, Leeds, Glasgow, Sheffield, Bradford and Bristol.

All that in 15 years! And where is the money to come from when the government is borrowing £1 for every £4 that it spends?...Already maternity units are under pressure, some primary schools are running out of places and housing is coming under increasing strain. Indeed, for the next 20 years or so, we will have to build a new home every seven minutes, night and day, just for new immigrants and their families. Where will they be built?” Currently, net migration to the UK is 216,000 in 2011, down from over 250,000 in 2010. The Cameron government has promised to get this down to the level of tens of thousands by the end of this Parliament, “no ifs and no buts”.  That would be a large change in a short amount of time (around three years) and Green notes that:

“...to stabilise our population we need to get immigration down to about 40,000 net migration a year. That is a tall order but the alternative is an ever-expanding population in a country, England, which is already the fifth most crowded in the world. Nearly 80% of us believe that England is overcrowded; in London that is 85%. And that is to say nothing of the implications for our social cohesion.” There are the fears of those worried about immigration to the UK – the cost of services and utilities, the worry of over-crowding and the implications for social cohesion.  These are serious concerns and need to be thought about and addressed if countries intend to rely on immigration to sustain or grow their population in the future.