Rob Vos has been tracking global hunger for years, and he says until recently the mood among his fellow hunger experts was almost giddy.

Since 1990 the world had made so much progress curbing hunger that, in 2015, leaders met at the United Nations and vowed to eliminate hunger for good by 2030.

"We actually were saying, well, there's still some hurdles, but we can do this. We can end hunger within our generation," says Vos, formerly a key official at the United Nations Food and Agricultural Organization and now with the International Food Policy Research Institute, or IFPRI, in Washington, D.C.

But while at first glance the global trend lines still look promising, Vos says a closer look at the statistics reveal stubborn problems that threaten that rosy picture. Increasingly this year, he says, cracks are starting to show.

Take the latest data: An annual Global Hunger Index produced by IFPRI that rates countries on several criteria measuring both general undernourishment and child malnutrition. For several decades the world has made impressive strides. The share of people who don't get enough to eat dropped from about one-fourth in 1990 to less than one-eighth today. And taken on a global scale, an update released this month shows that the numbers have improved at the same steady clip as always.

But look at the nation-by-nation statistics and worrying signs emerge, says Vos. Based on a country's score IFPRI classifies its severity of hunger in categories ranging from low to moderate to serious, alarming and extremely alarming.

"There are actually quite a few countries that are in serious risk of hunger or alarming states of hunger," he says. Fifty-two of 106 countries for which data is available, to be precise. Not to mention another nine countries, including Somalia, for which complete data was not available but that still raise "significant concern."

Joining Somalia among the worst off: South Sudan, Yemen and Nigeria, where early this year the U.N. declared that a total of 20 million people in the four countries were at risk of famine.

In these countries violent conflict is mainly driving the food crisis. In others the problem is weather disasters, possibly fueled by climate change. And in some nations, such as Madagascar and Zambia, the overwhelming challenge is widespread extreme rural poverty.

Even in regions — such as Latin America — that do well overall, there are glaring exceptions, such as Venezuela, where political turmoil and economic mismanagement has created massive price inflation and food shortages, leading IFPRI to classify it at "moderate" risk of hunger.

National numbers can look overly positive as well, masking deep pockets of deprivation within countries.

For too long, says Vos the top-line good news has distracted policy-makers from the underlying bad news. But he says the declaration of famine in so many countries early this year has helped pierce the bubble.

Last month brought another troubling milestone. The U.N. announced that for the first time in years the absolute number of people without enough food — as opposed to the percentage — actually went up in 2016 to 815 million.

Vos is hoping this drumbeat of evidence will serve as a wake-up call.

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