A black ribbon is strapped around Karaniteny's straw hat: a symbol of mourning after she lost her 10-year-old daughter Vahana to the devastation of severe drought in October.

Vahana died after eating red cactus fruit, the only plant growing in the drought-ravaged district of Anjapaly in southern Madagascar, the poorest spot on the large Indian Ocean island.

Nearly a million people are hungry and in urgent need of food aid in the area, according to the World Food Programme (WFP), in a crisis that spells out the reality of global warming.

On Wednesday, the US National Oceanic and Atmospheric Administration announced that 2016 was the hottest of modern times -- the third year in a row to break records.

Forced to confront the impact of rising temperatures and recurrent droughts, residents in Anjapaly have resorted to desperate solutions.

"Pots, spoons, plates, clothes, mats and even water cans -- I have sold everything to buy cassava (a staple food). But it is still too expensive for us," says Karaniteny, a mother of 12.

So with nothing else to eat, people live on wild cactus.

"We don't eat anything but leaves and red cactus fruit," said Karaniteny.

"My daughter only ate that, she couldn't bear it. She fell ill. She began to lose weight and strength. Then she had diarrhoea and vomited at the same time. That's why she died."

Two of Karaniteny's children have migrated from Anjapaly to escape hunger.

"They took their misery with them," said the woman in her 40s, who is now forced to look after her visibly malnourished grandson.

Thin and with a swollen belly, he is four years old, but looks just two.

- 'Nothing left' -

"The consequences of hunger are that there are not many people left here now," said Tolia Bernard, mayor of Anjapaly, which has 20,000 residents trying to survive in what has been dubbed the capital of hunger.

"A lot of people have fled... because there is nothing left," he said.

Many children have dropped out of school because of lack of food, local people say.

Around 100 kilometres (60 miles) away, in the coastal town of Andranobory, Sarah-Esther, 50, struggles to feed her 10 children.

She makes about 1,000 ariary (30 US cents) a week from selling salt at a market.

"With the money, I buy two cups of rice," she said. Clearly not enough for the size of her family.

Due to the drought, farmers in the seven worst affected districts of Madagascar lost 80 percent of their crops last year, according to the United Nations Development Programme (UNDP).

Drinking water is scarce and usually several kilometres away. At the worst of times, it takes residents days of walking to fetch water.

A 20-litre jerrycan of water is sold for between 500 and 1,500 ariary (15 and 45 US cents), 25 times more than the price in the capital Antananarivo.

After five months of dryness, the first burst of rain fell in Anjapaly in mid-December and filled up gigantic potholes.

The muddy water is unfit for human consumption but Manankay, a local woman, scooped some into a plastic bucket to take home.

"It is with this water here that we prepare food because there is no other water than this," she said. "It makes us sick but we have to drink it."

- Aid needed -

According to the UNDP, at least 800 wells, boreholes and dams need to be built or repaired in the region to provide clean water.

The population is almost entirely dependent on food aid, with the WFP handing out food parcels once a month.

"People who are already poor have to share the small amount of food they receive," said mayor Bernard.

"If there were at least one or two distributions a week, it still wouldn't be enough, but at least there would be something to eat."

The WFP says it needs $30 million of additional funds to feed the region's inhabitants.

"In view of our resources, we only distribute half rations," explained WFP's emergency aid expert Jean-Luc Siblot.

Scientists say the main reason for higher global temperatures is burning of fossil fuels that send carbon dioxide, methane and other pollutants known as greenhouse gasses into the atmosphere.

Another factor has been the Pacific Ocean warming trend of El Nino, which exacerbates warming.