There most probably more people of British descent across North America and Australia than in Britain. Same goes for Germans, Italians, Dutch and many other European ethnic groups. There are up to 40 million Irish people in the United States alone, but just over 6 million in Ireland itself. 40 million Spanish in Spain, but possibly hundreds of millions of their descendents across the Americas.
If Europeans didn't begin colonising the world would countries like the UK and Germany have 2 or 3 times more people living in them right now? Or are there so many white people across the world because colonising new land helped their population grow? Can someone also explain the strange Irish statistic because I'm puzzled at how huge the Irish diaspora is considering how small their homeland is.
Short answer: Kinda-Sorta
Long Answer: it wasn't necessarily the colonization of the new world, but the trade goods imported to Europe. The food of the Americas has much greater caloric value per gram than many native European foods. In particular, corn and potatoes are very rich in calories. While corn didn't catch on in Europe, potatoes surely did. We can hardly think of Irish, English and German cuisine without thinking of some delicious spuds. Anyways, better fed populations tend to grow at increased rates due to better health. However, it should be noted that we didn't begin to see MAJOR population growth in Europe until the industrialization of the agricultural process in the latter half of the 18th century.