More than one million Syrian refugees have now fled to neighboring Lebanon, the Untied Nations announced Thursday.
The U.N. Refugee Agency (UNHCR) called it a "bleak milestone" in the Syrian civil war that has killed more than 100,000 people and shown little sign of abating since it broke out in 2011. It also highlighted that Lebanon now has the highest concentration of refugees in the world.
If the same proportion of refugees came to the U.S., the influx would approach the combined population of California and New York.
"The influx of a million refugees would be massive in any country," U.N. High Commissioner for Refugees Antonio Guterres said. "For Lebanon, a small nation beset by internal difficulties, the impact is staggering."
He added: "The Lebanese people have shown striking generosity, but are struggling to cope. Lebanon hosts the highest concentration of refugees in recent history. We cannot let it shoulder this burden alone."
About 9.5 million Syrians have been forced to leave their homes. Most of these have been internally displaced, but some 2.5 million have been forced to flee their country. After Lebanon, Turkey has the most Syrian refugees, with more than 660,000, followed by almost 600,000 in Jordan, 220,000 in Iraq and 135,000 in Egypt.
Half of those in Lebanon are children. According to UNHCR, there are now so many Syrian refugees in the country that they make up one quarter of the population.
The CIA World Factbook puts Lebanon's population at just under six million, meaning that roughly one-sixth of its residents today are Syrian refugees. Using that more conservative estimate, the influx from Syria to Lebanon is the equivalent of 52 million people flooding into America. That's not far off the combined population of California and New York.
The refugee crisis has put Lebanon and Syria at the very top and bottom of world population growth, according to 2014 figures in the CIA World Factbook. Lebanon is growing at a rate of 9.37 percent each year, more than twice that of the second fastest, Zimbabwe.
Syria is almost a mirror image, losing almost ten times as many people as any other country on earth (bar the tiny Cook Islands) and shrinking at a rate of 9.73 percent. In comparison, the population of the U.S. is growing at 0.77 percent per year.
The strain has been emphatic. The World Bank estimates that the crisis cost Lebanon $2.5 billion last year alone, with plummeting wages threatening to push 170,000 Lebanese into poverty.