Sustainable Business: Feeding the changing world

Changing climate conditions will impact on all sectors of food production including horticulture and aquaculture. Photo / Supplied

Climate change is set to transform New Zealand food production. Rising temperatures, changing wind and rainfall patterns, increased carbon dioxide in the air will all have an impact. The food sector will feel the effects of this across the board. Meat and wool, dairy, arable farming, horticulture, viticulture, aquaculture and forestry will all face challenging new conditions.

A project set up by the Ministry for Primary Industries Sustainable Land Management and Climate Change Fund set out to forecast the likely effects on food production across the sector. It goes on to suggest ways farmers and primary industries can adapt. The goal is to help the sector prepare so it can maintain performance.

In its report Adapting to climate change: Information for the New Zealand food system, the project team summarises the findings and examines in some depth the potential changes each major food production sector faces in coming years.

New Zealand's climate has already changed. Air and sea temperatures have risen by 1C since 1910. Today the sea level is around 20cm higher than it was in 1910. We are already seeing more variable rainfall patterns.

The report looks at climate change predictions for the next 50 to 100 years. Different parts of the country will experience different changes.

The report suggests areas in the north of the North Island will become dryer and warmer in coming years. Farmers in these areas face a greater likelihood of drought.

Meanwhile warmer temperatures in these regions will bring challenges for getting fresh produce to market. There is going to be an increased risk of food spoilage. A possible mitigation would be for supply chain companies to use more refrigerated vehicles and operate cool storage facilities.

Changes in the North will have a different impact on food production to the expected climate change in the west and south of the South Island. In these areas rainfall is likely to increase. In those areas farmers can expect to see more flooding and humidity.

We can expect to see more extreme weather across the country. There will be higher wind speeds which could harm livestock or cause damage to crops and agricultural infrastructure. Rising sea levels will mean some pastures will no longer be usable. Salty water may inundate low lying areas and farmers will have to switch to other forms of production.

New Zealand's food production is already regionalised with different sub-climates being suitable for different types of farming. It's likely climate change will strengthen regional differences and shift production zones within the country.

Areas where water availability becomes limited thanks to climate change may no longer be suitable for, say, dairy farming.

Climate change may affect the geographic range of parasitic infection in animals. This will need more treatments and that could increase human exposure to these chemicals in food. Farmers can expect to see different growing season patterns emerge.

The dairy sector

Higher temperatures and changes in rainfall may allow the spread of new pests to threaten dairy herds.

This can include fungal toxins appearing in stored animal food.

Farmers will need to improve feed handling and storage.

An increase in heavy rainfall and flooding could contaminate the feed and water needed for stock. This increases the risk of waterborne diseases. Farmers will need to strengthen on-farm food and water safety management.

Higher humidity could lead to the spread of facial eczema. Changing breeds and using genetically resistant animals can help mitigate this. Farmers will also need to monitor spore counts during danger periods and either dose animals with zinc or spray fungicide on pastures.

If there are natural disasters animals may be crowded together for long periods increasing the transmission of diseases. We can also expect more animals to face heat stress.

The changes won't all be negative; dairy and meat farmers in some parts of New Zealand, especially the South Island, may benefit as higher levels of carbon dioxide, more rain and warmer temperatures are likely to increase pasture production.

We know dairy farmers in other countries already work with the conditions we are likely to experience in New Zealand, so there is a wealth of knowledge to draw on.

The meat sector

Many of the challenges facing the meat sector mirror those with dairy farming. Heat stress, potentially lower levels of reproduction and stock feeding are all similar. Likewise, the threats from parasites, pests, diseases like facial eczema and animal crowding after extreme weather emergencies. Potential problems arise with the carcass food chain and contamination affecting food safety.

The report authors suggest changing animal breeds or by using genetics to breed suitable qualities for dealing with heat will help address these issues.

Arable farming

Higher temperatures and rainfall may increase crop diseases. Farmers can counter this risk by using new resistant crop types and new species. There is also a likelihood of new weeds appearing on farms.

Farmers may need to use more pesticides.

Flooding could contaminate land, spreading antibiotic-resistant organisms and increasing fungal growth. This presents a disease risk to consumers of those crops. Farmers will need to strengthen food safety management and apply integrated management of water sources, soil, manure and any wildlife intrusion.

Rising sea levels will change the availability of suitable land. Seawater may find its way into farming areas. Farmers will need to use salt-resistant crop types and new species. They will need to change land use and, where viable, invest in mitigation.

Horticulture

Flooding could see an increase in pathogens from animal faeces as waters run off neighbouring properties. Farmers will need to strengthen food safety management.

Flooding could also see fertiliser and chemical residue from neighbouring land contaminate horticultural land. Farmers will need to strengthen farm and food safety management programmes.

Horticultural land will need to move to dedicated areas.

Higher temperatures will affect plants that need winter chilling. Farmers will need to move production of some of these crops further south. Both arable farming and horticulture will face an effect where greater concentrations of carbon dioxide will stimulate plant growth.

It's likely this will increase the output of carbohydrates, but at the expense of protein and essential minerals. That will have a negative effect on human nutrition.

Seafood and aquaculture

Changing climate conditions will impact on all sectors of food production including horticulture and aquaculture. Photo / Supplied

The waters around New Zealand are likely to get warmer and become more acidic. With heavy rainfall and floods expected on the land, there will be greater run-off. We can expect to see more heavy metal dioxin concentration in predatory fish, algal blooms, more toxins in general and shellfish diseases. For now, New Zealand is the only source of farmed salmon not treated with therapeutics. Higher temperatures may change this.

Sanford has already closed its Christchurch mussel processing plant because of warmer sea temperatures. The researchers see increased risks in the supply chain with the need for high food safety management and increased monitoring of blooms. Chilling food will become more important, and the cost of chilling will increase as temperatures rise.

● The project team included members from the New Zealand Food Safety Science and Research Centre partners: ESR, AgResearch and Massey University. There was also input from the National Institute of Water and Atmospheric Research (NIWA).

• Published in the Herald's 2021 Sustainable Business report