Climate change in Canterbury
Climate change is already having visible effects in the Canterbury region, and these will continue to become more apparent over time. Temperatures are warming and weather patterns are shifting, and these changes will have both positive and negative effects for different activities across the region. It is important that we understand the forecast impacts of climate change, so we can factor this into our planning and the work that we do.
Forecast impacts of climate change in Canterbury
We work alongside other agencies, such as Crown Research Institutes and universities to ensure our modelling work reflects the latest knowledge of climate change possibilities. The information below is taken from work by the National Institute of Water and Atmospheric Research (NIWA), downscaling global predictions to the New Zealand context.
- The strongest effects are expected in east Christchurch (particularly the lower Avon) and Washdyke, with the areas vulnerable to increased flooding, where it can’t get out through an estuary or lagoon.
- The intermittently closed and opened lakes and lagoons (Te Waihora/Lake Ellesmere, Wainono and Wairewa), opening regime will become vulnerable as it requires higher lake levels for effective opening.
- An increase in coastal erosion by 20% (a tentative prediction).
- Less frost inland and a longer growing season provides opportunities for different land uses.
- South Canterbury is predicted to get wetter towards the end of this century. Increased flows are predicted in alpine rivers, particularly in winter and spring.
- A higher river flow reliability in South Canterbury, due to it being wetter.
- Mid-range estimates show temperature increases of about 0.8 degrees Celsius by 2040 and 1.4 degrees Celsius by 2090.
- Higher evaporation across the Canterbury Plains, leading to increasing irrigation demand (a 20-30% increase in irrigation demand by 2090). Higher irrigation demand does not automatically lead to greater water abstraction. Irrigation efficiency within schemes and on-farm can meet most of this demand.
- Soil moisture deficits and drought will be more extreme on the Canterbury Plains and Banks Peninsula, but there will be less drought in South Canterbury.
- Lower stream flow reliability in the hill country as it will be drier due to less rain.
- Increasing westerly winds means higher rainfall in the mountains, and drier on the east coast