MORE THAN 20 million people in four countries are at risk of starvation in the coming months, in what the United Nations has called the worst humanitarian crisis since World War II. But the global response to the emergency has been lacking, both from governments and from private citizens. As of Monday, the U.N. Office for the Coordination of Humanitarian Affairs was reporting that only 43 percent of the $6.27 billion needed to head off famine this year in Yemen, Somalia, South Sudan and Nigeria had been raised. A poll by the International Rescue Committee showed that 85 percent of Americans are largely uninformed about the food shortages. The IRC calls it “likely the least reported but most important major issue of our time.”

Accounts by the United Nations, the U.S. government and private aid groups more than back up that claim. More than half the populations of Somalia and South Sudan are in need of emergency food assistance, according to the U.S. Agency for International Development. Civil wars in those countries have combined with meager spring rains to drastically reduce food supplies. In Nigeria, some 5 million people are at risk in the northeastern provinces where the terrorist group Boko Haram is active.

The most harrowing reports come from Yemen, where the United Nations says a staggering 20 million people need humanitarian aid. In addition to millions who lack food, more than 330,000 people have been afflicted by a cholera epidemic since late April, with one person dying nearly every hour on average. Donors have supplied less than 40 percent of the aid Yemen needs to prevent starvation, and officials have recently been forced to divert some of that assistance to fight cholera. In all four countries, children are disproportionately affected: Aid groups say 1.4 million severely malnourished children could die in the next few months if more help is not forthcoming.

The United States has responded relatively generously to U.N. appeals, thanks largely to Congress, which inserted an extra $990 million in food aid for the four countries into this year’s budget. Aid officials complain that the Trump administration has been sluggish in distributing the funds, but this month USAID announced an additional $630 million in aid, bringing the U.S. total since November to $1.9 billion. Unfortunately, U.S. security policy is helping to exacerbate the crisis that the aid is meant to stem: In Yemen, the Pentagon continues to back a misguided military intervention led by Saudi Arabia that has choked imports of food and medicine.

With public awareness still lagging, one encouraging development has been the formation by eight large U.S. private relief organizations of an unprecedented alliance, the Global Emergency Response Coalition, which on Monday launched a two-week fundraising drive. The campaign has attracted backing from several U.S. corporations, including Blackrock, PepsiCo and Google; funds raised will be divided equally among the relief groups and used for aid in the four countries as well as six of their neighbors. The groups correctly make the point that further delays in aid, whether because of a lack of donations or bureaucratic slowness in distributing them, will translate directly into more avoidable deaths. “The crisis,” says Carolyn Miles, the chief executive of Save the Children, “is really reaching a peak.”