Ensuring nutritious, safe and affordable food supply for a growing global population is a key challenge for many nations and New Zealand’s role in this supply chain is no exception.
Variations in rainfall, temperature, drought, wind patterns, fluctuations in sea level, conditions that allow weeds, pests and microbes to flourish and changes in atmospheric CO2 or ozone level – all associated with climate change – pose a risk to agriculture.
Whether plant or animal based, all food production ultimately needs soil derived nutrients, atmospheric carbon dioxide and sunshine. Yield reliability is almost entirely linked to consistency of water supply for plant growth.
A western diet, often high in sugars, fats and animal-based protein takes in the order of 1-1.2 hectares per person of land to grow the ingredients. By comparison, a subsistence diet based on grains takes closer to 0.2ha to feed a person; realistically this is only to a level above famine classification.
New Zealand has about 14 million hectares of land with high production potential, and a low population which is approaching 5 million people. This means New Zealand’s land and water resources can, and do, support food supply to millions of consumers around the world as well as sustaining internally.
With the New Zealand Government’s announced proposal to recognise and protect our most fertile and versatile land and its action for healthy waterways policy there has been increased discussion about land and water availability for food production. Those conversations sit squarely in the decisions around adaptation to climate change and how future weather patterns may affect food production land suitability.
With changing climate conditions, we may see crop production rates and efficiency of resource use climb; new crops previously unseen in some regions may emerge in response to increased temperature, rainfall and available carbon dioxide.
There are now some successful plantings of bananas in Northland and some interest in coffee, albeit at trial levels. Both products are normally grown in the tropical Pacific Islands or northern Queensland and Africa.
Conversely, we may see a decline in some temperate crops as suitable climate zones move away from areas that become hotter and drier. Plants such as kiwifruit require cold winters, so higher temperatures in growing regions would have a massive impact.
The draft National Policy Statement for Highly Productive Land (NPS-HPL) proposes a nationwide approach to protecting our most productive food producing areas from urban sprawl to ensure there’s enough land available for primary production now and in the future.
In a country with abundant natural freshwater resources, incorporating productive land use within catchments through careful harvesting of enough water for reliable food production, and the protection of natural water bodies from contamination is a fine balance that needs to be driven by sound science and human centric inputs. Our food production industry is heavily investing in this and is on the pathway to be recognised as one of the most sustainable in the world.
WSP’s work in the agriculture sector is focused on the establishment and operation of water storage and distribution infrastructure, and how management of nutrients and sediments can be improved through adoption of good environmental management practices.