New Zealand’s land-based primary industries & climate change: Assessing adaptation through scenario-based modelling

45 New Zealand's land-based primary industries & climate change: Assessing adaptation through scenario-based modelling The land-based primary industry sectors are essential to New Zealand's current and future export earnings. Evaluations of the impact of climate change and climate variability on the land-based sectors has to date been restricted to considering the sectors at a regional level. However, the business or enterprise level will have a key role in adaptation to climate variability and change. Here we explore the use of systems modelling to investigate adaptation in three sectors: forestry, arable, and pastoral. The impact of climate change on the risk from diseases in individual forests within and across regions of New Zealand was investigated using systems modelling. The modelling highlighted the differences, both within and between regions, in the likely susceptibility of individual forests to fungal diseases. The second case study was from the arable sector. The modelling identified the opportunities for businesses to benefit from faster maturing crops with increased productivity due to CO 2 fertilisation. Capturing the opportunities for arable business will require increased inputs of both nutrients and water. This raises issues for future irrigation needs and the vulnerability of dry land arable businesses. The third case study, a Manawatu dairy farm, modelled the impact of climate change on the pastoral sector. This region is predicted to have similar or higher productivity, compared to present-day conditions, with a changing climate. The modelling of a farm system identified the challenges to managing declining pasture quality over time as C4 grasses invade pastures. Adaptation measures that were modelled included earlier calving dates and increased cow numbers which were required to maintain high quality pastures. The modelling did not consider the impacts of multiple external pressures on the potential for a business to adapt to climate change, for example, the impact of an emissions trading scheme or nutrient caps. The three modelling case studies illustrate that there is already considerable adaptive capacity in New Zealand's primary sector based on technologies and management practices that are currently known. The challenge lies in how well the primary sector can adopt existing and future technologies and incorporate them into their production systems in the future.