HPC-powered modelling shows heat, animal illness and drought risks could affect NZ agriculture with changing climate

The Challenge:
A warming climate poses a range of risks across different agricultural sectors in New Zealand

The Solution:
A collaboration of researchers across three Crown Research Institutes developed a set of models ranging in complexity to outline risks and opportunities for arable, horticultural, and pastoral land uses. The models involved very data and computationally intensive processes, meaning access to NeSI was an essential component to their work.

The Outcome:
Inights from this recent study and future research in this space will help the agricultural sector with future adaptation planning and developing resilience to climate change.

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 and relied on access to NeSI's high-performance computing resources to build the models.

Computationally intensive calculations

Funded by two National Science Challenges – Our Land and Water and The Deep South – the Whitiwhiti Ora – Land Use Opportunities study aimed to assess the impact of climate change on agriculture in New Zealand. More specifically, the researchers wanted to use the  Intergovernmental Panel on Climate Change (IPCC) risk assessment framework and future climate scenarios to develop maps of key risks in New Zealand. The IPCC is the United Nations body for assessing the science related to climate change.

"Two important components of the IPCC framework are Hazard and Vulnerability. In this project, we took key hazards such as drought and temperature and developed indices of key vulnerabilities of specific crops and animals to these hazards. So for example, we looked at heat stress for cows and wheat, and water stress for pasture and maize," says Manaaki Whenua researcher Dr. Linda Lilburne. "Calculating these indices for different crops and climate scenarios as well as building the risk indices are data and computationally intensive processes, which is why we wanted to use NeSI."

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.

Exploring a range of scenarios

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.

Questions left to answer 

While this recent study has uncovered valuable insights, it's also highlighted the need for ongoing investigation and analysis.

"The new maps are a powerful step forward in understanding and displaying the effects of climate change for the primary sector in New Zealand," says Linda. "But, there are still many questions to answer, especially about the timing of hazards or opportunities in the future. For example, are droughts becoming more frequent or longer, or will increasing pasture production mean that high-country farms are better able to finish their lambs?"

To address these questions, the researchers suggest that work is now needed with farm systems scientists and agricultural experts to develop detailed interpretations of the climate change impacts for a range of different farm types, locations and commercial interests.

This research will help the agricultural sector with future adaptation planning and developing resilience to climate change.

Access to powerful computing resources that can handle these computationally intensive research questions, will remain a vital part of their work.

(This case study was adapted from an article that was published by Manaaki Whenua in Phys.org.)

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