Image copyright AP Image caption Many farmers in developing nations are vulnerable to natural disasters and risk losing their livelihoods

Farmers in developing nations bear the "major brunt" of natural disasters yet only receive a small percentage of post-disaster aid, says a UN report.

The Food and Agriculture Organization assessment said the sector experienced almost a quarter of the cost of damage caused by natural disasters.

However, despite being vital for food security and livelihoods, it received less than 5% of post-disaster aid.

The study was published at the UN World Conference for Disaster Risk Reduction.

Image copyright AP Image caption Cyclone Pam caused "unprecedented damage" to Vanuatu's economy, including its fishing fleet

Delegates from the FAO also announced the launch of a facility that will focus on bringing together technical expertise and financial resources with the aim of building greater resilience within the agriculture sector to natural extreme weather events.

"Agriculture and all it encompasses is not only critical for our food supply, it also remains a main source of livelihoods across the planet," said FAO director-general Jose Graziano da Silva.

"While it is a sector at risk, agriculture also can be the foundation upon which we can build societies that are more resilient and better equipped to deal with disasters."

He added that building resilience among the global farming community was one of the FAO's top priorities.

'Information gap'

The FAO assessment said between 2003 and 2013, natural disasters and hazards in developing nations affected more than 1.9 billion people and the cost of the damage was estimated to be in excess of US $494bn.

However, the exact impact on the agricultural sector was unreported and "therefore unknown".

It observed: "There is a critical information gap in terms of the quantitative economic impact of disasters on agriculture and on the livelihoods and food security of the populations affected.

"FAO has undertaken a study to fill this information gap and to quantify - where possible - the impact of natural hazards on the agriculture sector in developing countries over the past decade."

Researchers based their assessment on 78 "post-disaster needs assessments" from 46 nations between 2003 and 2013.

The team's preliminary findings include:

When droughts occur, the agriculture sector absorbs up to "84% of all economic impacts"

Within the sector, 42% of assessed losses were to crops (flooding was responsible for 60% of the damage; storms were responsible for 23%)

Livestock was the second worst-affected activity, accounting for 36% of the damage total

Asia was the most affected region, with estimated losses in the region of US $28bn

Africa was a close second, with losses of US $26bn

Mr Graziano de Silva said that he hoped the launch of the FAO's facility would help curb future losses.

Image copyright Reuters Image caption Rising populations are expected to place an increasing strain on the global food system

"With this new effort, we are aiming to limit people's exposure to risk, avoid or reduce impacts where possible, and enhance preparedness to respond quickly when disasters occur," he explained.

Studies have suggested that for every dollar spent on disaster risk reduction, two to four dollars are returned in terms of avoided or diminished impacts, he added.

The findings of the assessment and details of the FAO's new agriculture resilience facility were presented at the UN World Conference on Disaster Risk Reduction, currently being held in Sendai, Japan.

Speaking at the conference, Baldwin Lonsdale, president of Vanuatu, told delegates that the damage on the Pacific island nation caused by category five Cyclone Pam was "unprecedented".

"This is a major calamity for our country," he said. "Every year, we lose 6% of our GDP to disasters."

He described the disaster as a "major setback for the country's development".

"It will have severe impacts for all sectors of economic activity, including tourism, agriculture and manufacturing.

"The country is already threatened by coastal erosion and rising sea levels, in addition to five active volcanoes and earthquakes."

The conference is due to close on Wednesday with the expected adoption of an agreement on ways to reduce mortality and economic losses from disasters.