Many of us are enjoying summer barbecues, picnics in the park and weekends at the beach with family and friends. For millions of children in the Horn of Africa, however, this summer has brought an unspeakable nightmare.

The worst drought in 60 years, rising food prices and chronic conflict have combined to produce the most severe humanitarian crisis in the world. In Somalia, Kenya, Ethiopia and Djibouti, the lives of 11 million people are at risk.

More than 2 million children are acutely malnourished; 500,000 are in imminent danger of death. Many families from Somalia are struggling to make their way to Dadaab, a vast refugee camp in Kenya, but some children are so weak that they are dying en route. Some mothers are faced with a grisly "Sophie's Choice"-like dilemma -- which child do I feed and which one do I allow to die?

Please, do not throw up your hands and stop reading. While this situation is horrifying and overwhelming, it is not hopeless. The suffering and death of these children is not inevitable. They can be saved, and the earlier we all step up to help, the more children will survive.

We cannot control where we are born any more than we can control the weather patterns that have spawned this monstrous drought. But we can control how we react to such news. We can bury our heads in the sand; we can turn away -- or we can decide to act.

Media coverage has so far unfortunately been very scant, perhaps because -- unlike earthquakes or tsunamis -- this is not a singular catastrophic event. It is a disaster that has been growing slowly and insidiously, pulling more and more families into its deadly grip each day.

Famine has been declared in two districts of southern Somalia, and if humanitarian assistance is not quickly ramped up, it will spread to all other regions of the south within one to two months.

This is already Africa's worst food crisis in 20 years. It's terrible to think that by the time the world starts paying attention, it will have become an even greater calamity.

So how do we stop it? One highly effective weapon is a nutritional peanut paste that may not look like much but actually has the power to pull a child back from the precipice of death-by-starvation. Packed with protein and vitamins, it is ready-to-use and does not need to be refrigerated or mixed with water.

UNICEF and its partners are distributing this miracle paste and other therapeutic foods at emergency feeding centers in Kenya and Ethiopia. Since malnutrition makes a child more susceptible to lethal diseases such as measles, UNICEF is also providing basic immunizations as well as clean water.

But resources are limited. In order to aid the millions in the cross hairs of this disaster, additional funding is essential. Without it, the need will quickly outpace our ability to meet it.

Just $10 can feed a child for 10 days.

Americans are a compassionate people. We have a history of coming to the aid of innocent people -- and particularly innocent children -- who are in harm's way.

After the Haiti earthquake in 2010, for instance, the swift and phenomenal generosity of U.S. donors helped prevent a second wave of deaths from malnutrition and disease in the months following the disaster.

We have a similar opportunity -- and obligation -- in the Horn of Africa. Let's all do what we can now, when our generosity matters most.

Wouldn't it be great if, several months from now, we can say that the support of Americans once again played a critical role in containing the world's gravest humanitarian crisis and saving thousands of children from certain death?

But if we do not come forward, and if these children die in great numbers, it will not just be malnutrition and disease that killed them. A scandalous lack of attention and compassion will also be to blame.

Caryl M. Stern is president and CEO of the U.S. Fund for UNICEF .