What are the expected changes in New Zealand’s climate out to 2120?
Using the latest models and some very sophisticated computer processing Niwa can given us projections of future climate over the next 100 years.
Temperature change projections
Projected temperature change shows an increase of:
0.8 C by 2040
1.4 C by 2090
1.6 C by 2110
The possible range of temperature increase are:
0.2 – 1.7 C (2040)
0.1 – 4.6 C (2090)
0.3 – 5.0 C (2110)
Rainfall change projections for winter and spring show an increase for the west of both the North and South Islands, with drier conditions in the east and north. This is due to westerly winds over New Zealand increasing during these seasons.
For summer it is likely that there will be wetter conditions in the east of both islands, with drier conditions in the west and central North Island
There is substantial variation around the country which will increase in magnitude as emissions increase.
Extreme rainfall is likely to increase in most areas, with the largest increases being seen in areas where mean rainfall is also increasing, such as the West Coast.
Drought severity is projected to increase in most areas of the country, except for Taranaki-Manawatu, the West Coast and Southland.
There are going to be more dry days throughout North Island, and in inland South Island.
What are projections?
Climate projection is the simulated response of the climate system to a scenario of future emission or concentration of greenhouse gases and aerosols, generally derived using climate models. Climate projections are distinguished from climate predictions by their dependence on the emission/concentration/radiative forcing scenario used, which is in turn based on assumptions concerning, for example, future socioeconomic and technological developments that may or may not be realized. (IPCC, IPCC, 2013: Annex III: Glossary)
Source: Ministry for the Environment 2016. Climate Change Projections for New Zealand: Atmosphere Projections Based on Simulations from the IPCC Fifth Assessment. Wellington: Ministry for the Environment.
Prepared for the Ministry for the Environment by Brent Mullan, Abda Sood and S. Stuart., National Institute of Water and Atmospheric Research (NIWA).