Impact of Tonga Volcanic Eruption on Agriculture

With the full picture of damage and needs after Tonga’s massive volcanic eruption and tsunami only gradually emerging, what is already clear is that the stakes could not be higher for the farmers and fishers of the South Pacific island nation, living in one of the world’s most disaster-prone regions.

With roughly 86 percent of Tongans engaged in agriculture, FAO is extremely concerned about the potential impacts across all agriculture sectors, including fisheries, crops and livestock. That is despite communications and access remaining severely affected. Initial estimates are that roughly 12 000 agricultural households or 85 percent of the total number, will have been affected by this disaster, according to Xiangjun Yao, FAO Subregional Coordinator for the Pacific Islands, based in Samoa.

“We’re working to assess how bad the impact of this disaster will be on Tonga’s farmers and fishers and all those who depend on forms of agriculture for their livelihoods and food security,” Yao said. “We have been providing support in Tonga after a series of shocks in recent years, of which this is by far the most serious and we are ready to ramp up our work to help these vulnerable communities get back on their feet.

One of the first challenges is assessing the possible impact that the layer of ashfall covering parts of the island, as well as the tsunami damage could have on agriculture and fisheries.

Serious potential effects from ashfall and tsunami

Ashfall can have serious detrimental effects on crops and livestock depending mainly on ash thickness, the type and growing conditions of the crop, the timing and intensity of subsequent rainfall, condition of pasture and animals prior to ashfall, and availability of uncontaminated feed and water.

Root crops, such as sweet potato and yams, could be affected, while fruit and vegetable crops across the archipelago are certainly also at risk. Saltwater inundation will also have likely affected farmland, and the possibility of acid rain is a concern.

FAO preliminary estimates indicate that 60-70 percent of livestock-raising households – mostly pigs and poultry – have had their livestock affected in some way. The expected impact on fisheries is also a cause for concern. While consumption of fish per capita is somewhat low for the Pacific (25-35 kg/year), fisheries could become a more important food source following this disaster, given potential effects of volcanic ash cover on land which produces local food supplies.

Damage to boat ramps and boats is already evident and many of the coastal reefs and lagoons on which healthy fisheries rely are likely to have been damaged or polluted with ash and debris as well as waste from the tsunami.

“With a comprehensive picture yet to emerge, it’s already clear that Tonga will likely require both short- and long-term assistance. FAO is already moving to allocate funds for damage assessments and some initial response measures,” said Yao.

Even before this latest eruption of the Hunga Tonga Hunga Ha’apai volcano, some 23 percent of Tonga’s population was affected by moderate to severe food insecurity.