By Emma Batha

LONDON, Dec 22 (Thomson Reuters Foundation) - The humanitarian catastrophe in Lake Chad basin, where conflict has left over 8 million people destitute with many "teetering on the brink of famine", was the most neglected crisis in 2016, according to a survey of aid agencies.

Following Lake Chad in a Thomson Reuters Foundation poll of 19 leading aid groups were Yemen, where children are starving, and South Sudan where U.N. Secretary-General Ban Ki-moon fears genocide is about to start.

Overshadowed by the wars in Syria and Iraq and the global refugee and migrant crisis, Lake Chad barely made the headlines this year, but aid organisations said the crisis was "on an epic scale" with "terrifying rates of child malnutrition".

"Syria broke my heart, but for out and out human suffering and almost zero media coverage, the food crisis sparked by Boko Haram in Nigeria and Niger was the pits," said Suzanna Tkalec, humanitarian director at Caritas.

Boko Haram militants have displaced 2.4 million people across Nigeria, Cameroon, Chad and Niger during a seven-year campaign to create an Islamist caliphate.

Oxfam said parts of northern Nigeria were already experiencing famine and Action Against Hunger warned many children were at risk of dying.

Almost 7 million people lack food but insecurity makes it hard for aid agencies to reach the most vulnerable.

International Medical Corps' programmes director, Ognjen Radosavljevic, said border closures had disrupted markets, agriculture was collapsing and food was unaffordable.

"It is essential that the global community wakes up to the horrors ... in this region," he added.

YEMEN "SHAMES US ALL"

Aid workers also warned of famine in Yemen where nearly two years of war between a Saudi-led Arab coalition and the Iran-allied Houthi movement has pushed the Middle East's poorest country to breaking point.

The crisis, exacerbated by restrictions on imports, has left over four fifths of the population struggling to find enough food and water to survive.

"That's the highest level of humanitarian needs in the world and yet Yemen has received negligible media attention," said Laurie Lee, head of CARE.

Eight in 10 children are stunted and every 10 minutes a child dies from preventable diseases, agencies say.

Some have warned that Yemen could run out of food within months.

"It is heart-breaking to already witness starving children," said Jan Egeland, head of the Norwegian Refugee Council, adding that all sides in the conflict were hampering aid deliveries.

"We must put an end to this man-made disaster that shames us all. If the situation is allowed to continue to deteriorate, it will result in famine across Yemen in 2017."

"OMINOUS SIGNS"

Several agencies sounded the alarm over South Sudan where there have been calls by the head of a U.N. human rights commission to deploy a 4,000-strong protection force to stop a "Rwanda-like" genocide.

"South Sudan passed the one million refugee mark this year, yet it is a crisis that has barely made the front pages," said Mercy Corps' director Craig Redmond, adding that the world's youngest country had overtaken Afghanistan as the most dangerous place to be an aid worker.

More than 3 million people have been uprooted by fighting, with 1.2 million seeking shelter in nearby countries.

Agencies said the response was chronically underfunded with the regional refugee plan getting only a third of the support it needed.

"In sheer scale it has become Africa's biggest displacement crisis. And as 2017 approaches the signs are ominous that more suffering is to come," U.N. refugee chief Filippo Grandi said.

The International Federation of the Red Cross (IFRC) and World Vision named the fallout from the powerful 2015-2016 El Nino weather phenomenon as the most neglected crisis, saying over 60 million people remained affected worldwide.

In southern Africa, El Nino-induced drought has devastated farms, killed off livestock and crippled food production, with "alarming consequences", said Garry Conille, IFRC's head of operations.

"It is the poor and vulnerable once again who are suffering disproportionately and far too quietly," added Conille, a former Haitian prime minister.

Libya and Myanmar, where renewed violence has uprooted many Rohingya Muslims, were also flagged up in the poll.

International Rescue Committee's policy director Sanjayan Srikanthan said Libya, which has made headlines for the refugees and migrants leaving its shores for Europe, was in crisis.

Instability and fighting has left more than one in five Libyans needing humanitarian assistance and displaced 240,000 people, he said, adding that the healthcare system was on the brink of collapse.

Several agencies expressed alarm at the sheer number of neglected crises.

Christian Aid said 2016 was notable for "an emerging chasm between need and response" which threatened to undermine the foundations of humanitarian aid. (Additional reporting Umberto Bacchi. Editing by Katie Nguyen. Please credit the Thomson Reuters Foundation, the charitable arm of Thomson Reuters, which covers humanitarian news, women's rights, trafficking, corruption and climate change. Visit news.trust.org to see more stories.)