Heat, Animal Illness and Erosion Risks to Affect NZ Agriculture With Changing Climate

By Manaaki Whenua

Scientists at Manaaki Whenua—Landcare Research have worked closely with researchers from NIWA, AgResearch and Plant & Food Research to model the likely risks of a warming climate across different agricultural sectors in New Zealand. The study is published in the Journal of the Royal Society of New Zealand .

The results—which broadly indicate that current crop ranges move south, and animal health issues intensify and also move south—are available as geographical information systems (GIS) layers for people to download at the Whitiwhiti Ora Data Supermarket.

To create the maps, a set of models ranging in complexity were developed to outline risks and opportunities for arable, horticultural and pastoral land uses. The models combined an overall assessment of climate hazard events such as heat stress and extreme rainfall with the vulnerability of specific crops and farm systems to these hazards.

Four different scenarios of future greenhouse gas emissions were modeled, including a worst-case scenario of a global mean temperature increase of as much as 4°C by 2100.

Results from the modeling—which are available off-the-shelf at the Data Supermarket—include the following likely changes:

• Heat stress may become more of an issue for the arable sector, especially for wheat farming areas, although rising temperatures and fewer frosts may bring new opportunities to crops such as onions, peas and potatoes in some areas.
• Cool-climate grape varieties may be able to move south, but grape ripening times will move closer together across the country, which might complicate harvest schedules.
• Pasture yields may increase, but also intestinal parasites and facial eczema in livestock may spread further in a warming environment, even under the most conservative climate change scenario.
• There will be more mass movement and erosion of soil, particularly in New Zealand's soft-rock hill country, driven by increasing storm magnitude and frequency.