But that's just an estimate, midway through 2013, of what will be needed in what is turning out to be an "unprecedented" challenge, said Valerie Amos, the U.N. Undersecretary-general for humanitarian affairs and emergency relief.
The likelihood is that as much as a third of what's needed won't be raised, according to the U.N.'s own figures. Over the past five years, the United Nations has only been able to scrounge up between 63 percent and 72 percent of what it says is required to feed, house and provide other help to the millions of people trying to survive often desperate conditions.
Amos, a British baroness who heads the U.N. Office for the Coordination of Humanitarian Affairs, said Syria alone requires at least USD 4.4 billion in aid for the 6.8 million people who are suffering inside the war-torn country and the 5.3 million refugees or others who are affected by the conflict in border nations.
"In a normal year, that would be a huge statement to the commitment to humanitarian action," she said of the USD 5.1 billion raised so far that has gone to people in 24 countries, including Syria, Niger, Sudan and Afghanistan. "But this is an extraordinary year.