sunalos Actually they are right. I remember reading that this was coming down the road back in the 80's when only Poland and Ireland were still replacing their populations. No one wanted to listen then and most are still not listening. No plitician will get re-elected if he/she admits they will ban contraception and abortion in order to save their country. Some countries have begun to take action with limited results (e.g. Sweden, France, Russia) but no country that I know of has gotten back above replacement rate once they've dropped below it.
It is unpalatable but true that mass immigration is what is needed as an emergency solution given that other, slower measures are unlikely to be adopted. Perhaps it was manufactured to happen or more likely it was incompetence and lack of foresight but Europe (and the US along with all the Western nations and more besides) have this problem. Unfortunately the social and cultural consequences of mass immigration, even from Christian countries, could outweigh economic benefits. There is also the problem of the impact on the countries of origin of those immigrants: they lose a lot of young working people.
One good book is Caldwell's Reflections on the Revolution in Europe (2013). If you have the time and the patience go to indexmundi and dig through the information there.