Story highlights 821 million people -- one in every nine -- were malnourished in 2017, up from 815 million in 2016

The UN says the situation is worsening in South America and most regions of Africa

(CNN) Climate change is having a negative effect on global agriculture and is driving up the number of hungry people around the world, according to the United Nations' 2018 State of Food Security and Nutrition in the World report, released Tuesday.

It found that 821 million people -- one in every nine -- were malnourished in 2017, up from 815 million in 2016, putting at risk the UN's goal of eradicating hunger in the world by 2030.

There was also limited progress in 2017 in addressing multiple forms of malnutrition, such as child stunting (in which children don't grow properly due to undernourishment) and adult obesity, putting the health of hundreds of millions of people at risk.

"Hunger has been on the rise over the past three years, returning to levels from a decade ago," the UN agencies responsible for hunger and health said in a statement.

"This reversal in progress sends a clear warning that more must be done and urgently if the Sustainable Development Goal of Zero Hunger is to be achieved by 2030."

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