Jess Lees was just 22 when she had her first test of courage as an aid worker.

She was deployed to Darfur, the semi-arid province of Sudan scarred by years of brutal conflict, enormous suffering and alleged war crimes.

"You can imagine what my parents thought," she says.

Now, at 28, Lees is already a veteran of some of the world's worst humanitarian emergencies. Last week she was in drought-ravaged Somalia, working out how the Australian Red Cross can best respond to a deepening food crisis.

About 6.2 million Somalis – half the country's population – are on the brink and United Nations Secretary-General Antonio Guterres warned last month that 185,000 children "could die soon if they do not receive urgent medical treatment".

Lees, who is the response manager at Australian Red Cross, was deeply worried by what she saw in the breakaway western region of Somaliland.

"I've worked on quite a lot of humanitarian responses over the past few years and unfortunately this is one of the worst I've seen," she says. "If the rains don't come the fear is that millions of people will be pushed into famine."

Lees' interest in international aid and development began during a trip to South America soon after she left school. After seeing the living conditions of vulnerable people in that part of the world, she decided on a career in the humanitarian sector.

Lees did a bachelor's degree in international studies in Melbourne and followed that up with a postgraduate degree in international crisis management. She had completed her initial year-long assignment in Darfur before finishing the master's.

Since then Lees has been deployed in a host of countries across Africa and the Pacific.

"This job reminds you of how big the world is and how fortunate we are," she says. "There are so many people living in extremely vulnerable circumstances. Even though we might be far away, I don't think we just can just turn the other way and avert our eyes to those needs."

It was striking how some of the village-level humanitarian workers that Lees consulted in Somalia described their own motivation in a similar way.

"I'm always ready to help poor people in my area, that's why I am here," says Noor Ismail, a nurse at a mobile clinic operating in remote settlements near the town of Hargeisa in Somaliland.

"To find so many malnourished children is heartbreaking."

Lees' most challenging assignment was leading a field team that co-ordinated emergency food drops in South Sudan for the United Nations' World Food Program (WFP) in 2015.

The team was routinely dropped by helicopter into remote locations to identify places where food supplies could be delivered to communities in dire need. Once an appropriate site was found the team would liaise with the WFP base by radio to co-ordinate the distribution. The team put markings on the ground so the WFP's giant Ilyushin cargo planes laden with food could accurately target the drop.

The method of distribution is only used in areas where armed conflict or poor security rule out truck transport.

Bad weather and logistical snags meant Lees' team often lived rough in tents for weeks at a time.

"Because of the whole host of challenges that a place like South Sudan has, there are inevitable kinks in the road and delays. That ends up having an impact on operations and you might end up being out in the field for much longer than you first anticipated," she says.

On one assignment Lees was away from base for 21 days. The waiting time was often frustrating.

"It wasn't a hard job intellectually but it was hard mentally and hard physically," she says. "I found out the mosquitos in South Sudan can be very bad."

Humanitarian agencies are moving away from simply handing out rations to vulnerable communities when food is scarce. Instead, they are providing more cash grants that allow beneficiaries to buy their own food. A market assessment is done to ensure supplies will be available for hungry families to purchase from local stores when they need it.

Aid groups say this strategy has proved much more efficient than large-scale food distribution. It also helps sustain local markets and food supply chains.

In her role at the Australian Red Cross, Lees is evaluating the possibility of supporting cash grant programs for communities threatened by famine, including in Somalia.

'Close to a breaking point'

The global humanitarian system is facing a year of unprecedented challenges.

International aid officials say a record 70 million people will need emergency food aid in 2017. Famine has already been declared in parts of South Sudan and three other countries could soon be in that category – Somalia, Yemen and Nigeria.

These emergencies have hit as international aid agencies struggle to respond to major humanitarian crises caused by the conflicts in Syria and Iraq.

"Right now, the scale of humanitarian crises from Syria to Somalia means we are close to a breaking point," Lees says.

"We urgently need to think and act differently to effectively respond to crises. Most importantly we need to prevent them from happening in the first place by investing more in local organisations and in countries most at risk of natural disasters and armed conflict. These are global crises with very personal solutions. It's more critical than ever that humanitarian partners, governments, businesses and communities work together to stop needless suffering."

But in each one of the world's worst emergencies, humanitarian work is being hampered by violent conflict. Indeed, security is a growing challenge for humanitarian workers like Lees.

A fortnight ago six aid workers were killed in a single ambush in South Sudan. It was the third serious attack against humanitarian workers in March alone. The dead were from South Sudan and neighbouring Kenya, illustrating how vulnerable locally born aid workers are to violence.

Attacks on aid workers, especially local employees, is frequent despite UN warnings that intentional violence against them "may constitute war crimes". At least 79 humanitarian workers have been killed in South Sudan since conflict erupted there a little over three years ago.

"Security measures for humanitarian organisations are increasing but that's not leading to a decrease in these incidents," says Lees. "It obviously has an impact on operations."

A case in point are the food drops that Lees was helping to co-ordinate in South Sudan. "They are by no means the most efficient way to distribute aid," she says. "It is very costly to set up a humanitarian air operation and sometimes the food gets into the hands of the wrong people. But one of the biggest reasons it has to happen is because of the security situation."

Lees says the biggest lesson she has gleaned from her humanitarian deployments is the importance of collaboration. "Co-operation and co-ordination are two really key things for humanitarian aid work," she says. "It is done in environments where things are moving really fast and the picture is changing constantly. You are going to be most efficient and effective if your aim is to get along with others."

Lees has also discovered that you're very likely to come across other Aussies in a disaster zone. "I think there've been Australians on every mission that I've been deployed to," she says.

"There's no doubt Aussies are very well represented in the humanitarian sector. A lot of them are real characters as well – passionate, hardworking but always available for some light-hearted comic relief when the time is right."

Matt Wade was supported by the Australian Red Cross to report from Somalia.

Donations can be made to the Australian Red Cross East Africa Food Crisis Appeal,UNHCR Australia and Oxfam.