As Syria's hideous civil war enters its fifth year, the conflict has now led to more than 4 million Syrians fleeing the country.

That's according to new numbers published in a report Thursday by UNHCR, the U.N.'s refugee agency. It also estimates that an additional 7.6 million Syrians remain displaced within the country -- meaning that roughly half of all Syrians have been forced from their homes since the war broke out in 2011.

It's a shocking statistic. "This is the biggest refugee population from a single conflict in a generation. It is a population that needs the support of the world but is instead living in dire conditions and sinking deeper into poverty," said U.N. High Commissioner for Refugees António Guterres, in a news release.

As the above map from UNHCR indicates, the bulk of Syrian refugees can be found in neighboring countries. In Lebanon, Syrian refugees now comprise a quarter of the overall population, a reality that has caused no shortage of friction and hardship for the new arrivals. In some Turkish cities, destitute Syrian refugees are becoming a ubiquitous sight, with homeless families camped out in parks and children begging in public areas.

Many who make it to Turkey carry on, embarking on harrowing journeys for a better life in Europe, as my colleague Tony Faiola chronicled in a lengthy expose last month.

The United Nations has made repeated entreaties for international humanitarian and development aid to ease the plight of Syria's uprooted millions.

UNHCR estimated it needed some $5.5 billion in 2015 alone to adequately fulfill its mission, but there is a massive funding shortfall. Here's from Thursday's press release:

A substantial proportion of this funding is intended to prevent the region’s main hosting countries from becoming overwhelmed and unstable. However, as of late June, less than a quarter of this sum (24 per cent) had been received. This means refugees face tough new cuts in food aid, and struggle to afford lifesaving health services or send their children to school.
Life for Syrians in exile is increasingly tough. Some 86 per cent of refugees outside camps in Jordan live below the poverty line of US$ 3.2 per day. In Lebanon, 55 per cent of refugees live in sub-standard shelters.

In 2014, according to a separate UNHCR report issued last month, the number of people displaced by war and persecution worldwide was "larger than in any year since detailed record-keeping began," as my colleague Griff Witte wrote.

One in five people in this tragic "nation of the displaced," UNHCR said, was Syrian.

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