We are called the Kāpiti Coast for good reason…our towns are largely coastal. Climate change is already having a major impact on the Kāpiti Coast with the council committing many $millions to constructing seawalls and increasingly there is talk of managed retreat.
The Ministry for the Environment provides an overview of how the climate in the Wellington and Wairarapa regions is likely to change into the future and what implications this has for the regions.
Projections of climate change depend on future greenhouse gas emissions, which are uncertain. There are four main global emissions scenarios ranging from low to high greenhouse gas concentrations. This page presents regional projections as a range of values from a low emissions to a high emissions future.
The projected changes are calculated for 20312050 (referred to as 2040) and 20812100 (2090) compared to the climate of 19862005 (1995).
Temperature
Compared to 1995, temperatures are likely to be 0.7˚C to 1.1˚C warmer by 2040 and 0.7˚C to 3.0˚C warmer by 2090.
By 2090, Wellington is projected to have from 6 to 40 extra days per year where maximum temperatures exceed 25 degrees, with around 5 to 13 fewer frosts per year.
Rainfall
Rainfall will vary locally within the region. The largest changes will be for particular seasons rather than annually.
Seasonal projections show that in winter Paraparaumu is likely to experience 5 to 13 per cent more rainfall by 2090 while Masterton is likely to experience up to to 7 per cent less rainfall.
According to the most recent projections, Wellington and Wairarapa are not expected to experience a significant change in the frequency of extreme rainy days as a result of climate change.
Wind
The frequency of extremely windy days in Wellington by 2090 is likely to increase by 2 to 3 per cent. There may be an increase in westerly wind flow during winter, and north-easterly wind flow during summer.
Storms
Future changes in the frequency of storms are likely to be small compared to natural inter-annual variability. Some increase in storm intensity, local wind extremes and thunderstorms is likely to occur.
Sea-level rise
New Zealand tide records show an average rise in relative mean sea level of 1.7 mm per year over the 20th century. Globally, the rate of rise has increased, and further rise is expected in the future.
The Ministry for the Environment provides guidance on coastal hazards and climate change, including recommendations for sea level rise, see Preparing for coastal change: A guide for local government in New Zealand.
