PARIS (APP) – The effects of climate change on food production could cause 500,000 extra deaths by 2050 compared to a world without global warming, according to a study released Thursday.

If greenhouse gas emissions continue at current rates, this would cut projected increases in food availability by about a third before mid-century, the study found.

As of 2015, some 800 million people in the world are undernourished, meaning they cannot meet daily minimum dietary energy requirements, the UN’s Food and Agriculture Organization has said.

With the global population set to increase from seven to nine billion by 2050, food production will have to expand even more rapidly if all the world’s people are to have enough to eat.

But global warming — on track to boost temperatures three degrees Celsius (5.4 degrees Fahrenheit) by 2100, compared to pre-Industrial-Era levels — is threatening to make that difficult or impossible, experts warn.

“Climate change effects are expected to reduce the quantity of food harvested, which could lead to higher food prices and reduced consumption,” according the study, published in the medical journal The Lancet.

Even these grim projections may be overly optimistic, it warns, because they only count calories and fail to anticipate a likely worsening in the balance of future diets.

“Our results show that even modest reductions in the availability of food could lead to changes in the energy content and composition of diets,” said Marco Springmann, a researcher at the Oxford Martin Programme on the Future of Food at the University of Oxford, and leader of the study. “These changes will have major consequences for health.”