Opportunities and risks
A changing climate is expected to create both opportunities and risks for New Zealand:
- Warmer winters are expected to reduce electricity demand, increase rainfall in the mountains and reduce snow cover; thereby increasing hydroelectric lake levels and reducing electricity supply pressures.
- Agricultural and forestry productivity is expected to increase in some areas, as will the potential for commercialisation of new crops. However, increased drought and other extreme weather events are expected to cost the sector, particularly in areas already affected by water shortages or flooding. Higher temperatures could also affect crops such as kiwifruit that require cold winters for fruit development. There would be costs associated with changing land-use activities to suit a new climate.
- Agricultural and forestry pests and diseases could spread more easily in warmer conditions, and forest fires are also likely to become an increasing risk in some areas.
- Heavier rainfall is likely to put increased pressure on drainage and stormwater systems. Erosion from more frequent flooding may increase road maintenance costs, but fewer snowfalls during winter would save road maintenance costs in some areas.
- Droughts may become more frequent in eastern areas, but floods after major downpours are likely to increase across the country. Increased flood risks are expected both from rivers during extreme storm events, and from coastal inundation from elevated sea levels (see below), which may be exacerbated by flooded rivers backed up by high tides and/or obstructed river mouths.
- A rise in sea level sea is expected to exacerbate coastal erosion and coastal flooding (especially at times of king tides and/or storm events), drainage problems in low-lying areas, salinisation of coastal rivers and streams, saltwater intrusion affecting inland aquifers and ground water, and inundation of low-lying areas.
