Imagine having to pick just one of your children to save, while leaving the others to face death.

One of my most searing experiences as a reporter occurred in Cambodia, where I met a woman whose daughter had just died of malaria and who was left caring for seven children and grandchildren.

The woman, Nhem Yen, showed me her one antimalaria bed net and told me how every evening she agonized over which children to squeeze under it — and which ones to leave out and expose to malarial mosquitoes.

That's the kind of excruciating question that extreme poverty forces on families.

For thousands of generations, a vast majority of humans have lived brief, illiterate lives marked by disease, disability and the loss of children. As recently as 1980, a slight majority of the world's people lived in extreme poverty, defined as surviving on less than $1.25 in today's money.

Yet in a time of depressing news worldwide, about dysfunction and crisis from Syria to our own Congress, here's one area of spectacular progress.

The share of the world's people living in extreme poverty has been reduced from one in two in 1980 to one in five today, according to the World Bank. Now the aim is to reduce that to almost zero by 2030.

There will still be poverty, of course, just as there is far too much poverty lingering in America. But the extreme hanging-by-your-fingernails subsistence in a thatch-roof hut, your children uneducated and dying — that will go from typical to essentially nonexistent just in the course of my adult life.

Here's something even more important than congressional name-calling or the debt limit: New approaches are saving millions of children's lives each year. In 1990, more than 12 million children died before the age of 5. Now that figure is down close to 6 million. Bill Gates, whose foundation with his wife, Melinda, pioneers the vaccines and medicines saving these lives, tells me that in his lifetime the number will drop below 1 million.

Illiteracy is retreating, and technology is spreading. More people worldwide now have cellphones than toilets.

Time out for a skeptical question that is both callous and common:

When additional kids survive in poor countries, does that really matter? Isn't the result just a population explosion leading to famine or war, and more deaths?

That's a frequent objection, but it's wrong. When child mortality drops and families know that their children will survive, they are more likely to have fewer babies — and to invest more in them. There's a well-known path from declining child deaths to declining births, which is why Bangladesh is now down to an average of 2.2 births per woman.

Ancient diseases are on the way out. Guinea worm and polio are likely to be eradicated in the coming years. Malaria has been brought under control in many countries, and a vaccine may reduce its toll even further.

AIDS is also receding. Last year in southern Africa, I interviewed coffinmakers who told me grumpily that their businesses were in recession because AIDS is no longer killing large numbers of people.

The drop in mortality understates the gains, because diseases don't just kill people but also leave them disabled or unproductive, wrecking the economy. Poor people used to go blind routinely from disease or were unable to work for want of reading glasses. Now they are much less likely to go blind and far more likely to get glasses.

These achievements aren't just the result of work by Western donors or aid groups. Some of the biggest gains resulted from economic growth in China and India. When the poor are able to get jobs, they forge their own path out of poverty.

Rajiv Shah, the administrator of the U.S. aid agency, says he is optimistic that extreme poverty will be eliminated by 2030 but notes that increasingly the focus will have to be on lagging countries like Congo. Aid groups are everywhere in countries like Rwanda or Malawi that are easy to work in, but scarce in eastern Congo or the Nuba Mountains of Sudan, where the needs are desperate but working conditions can be dangerous and primitive.

Despite the gains, a Pew poll early this year found that the budget area that Americans most wanted to cut was "aid to the world's needy." Perhaps one reason is that aid groups and journalists alike are so focused on problems that we leave the public mistakenly believing that the war on poverty and disease is being lost.

So let's acknowledge that there's plenty of work remaining — and that cycles of poverty in America must be a top priority at home — yet also celebrate a triumph for humanity. The world of extreme poverty and disease that characterized life for most people throughout history may now finally be on its way out.