By: Mark Leon Goldberg on March 14, 2014The crisis in Syria is entering its fourth year and there is no end in sight. Tomorrow, the moment is being commemorated across the globe. If present trends continue, one year from now we will be commemorating the start of another year of war.Beyond the extreme suffering of millions of Syrians, a mass exodus from Syria has placed severe strains on neighboring countries. As of today, 2.5 million Syrians have registered as refugees in neighboring countries or are awaiting registration. Another 6.5 million Syrians are displaced inside the country. That means that about 40% of the entire pre-conflict population of Syria has been displaced.Lebanon and Jordan — two fragile countries — are shouldering most of the burden. But I don’t think that most people understand just how much of a burden this is. These statistics from the UN Refugee Agency are eye opening:In Lebanon alone, the number of registered refugees from Syria is approaching 1 million and could grow to 1.6 million at the end of 2014 if current trends continue. Lebanon already has the highest per capita concentration of refugees of any country in recent history, with nearly 230 registered Syrian refugees for every 1,000 Lebanese.That is more than 70 times as many refugees per inhabitants as in France, and 280 times as many as in the United States. The number of registered Syrian refugees hosted in Lebanon would be equivalent to nearly 19 million refugees in Germany and over 73 million in the United States.This is a crisis that is undermining the stability of countries in a fragile region of the world. We have to assume that the international community will be dealing with its consequences for many, many years to come.