Climate Projections for New Zealand by 2040 and 2090 according to NIWA

NZ Herald reports a 38.2 C temperature in Gisborne on 31 January 2020, the hottest since 1940 and the country’s fifth warmest January temperature that NIWA recorded. However, the Met Service station recorded it as slightly cooler at 37.1C (Neilson, 2020).

NIWA, or the National Institute of Water and Atmospheric Research, is a research institute in New Zealand whose mission is to conduct leading environmental science to enable the sustainable management of natural resources for the country and the planet.

On 2 February 2020, Newshub also reported over 35°C temperature around the country, fearing it could go over 4°C in some eastern parts of New Zealand. NIWA says on its Facebook page that “sea temperatures around New Zealand have really warmed up” and adds that the hot sea temperatures in the Pacific could lead to more destructive weather patterns in the second half of February 2020 (Palmer, 2020).

What used to be the cool seas in the north of Australia have been replaced by warmer seas, which cause a rising motion in the Atmosphere, creating rain and thunderstorms, says NIWA meteorologist Ben Noll on Hub news (Palmer, 2020).

Climate change projections for NZ

Will these high temperatures become a trend every summer season in the future, and will there be a steady increase in the temperature in the coming years?

The Ministry for the Environment (MFE) has published a report on New Zealand’s future climate projections based on the IPCC’s 5^th assessment report.

The full report may be read through the link below

Climate Change Projections for New Zealand, Atmospheric projections based on simulations undertaken for the IPCC’s 5^th Assessment 2nd edition

A summary of the report says that climate change results from increasing amounts of greenhouse gases in the atmosphere. In New Zealand, changes in key climate parameters like temperature and rainfall are already felt.

Climate change projections will not happen this year or the next few years but in 2040 and 2090.

However, NIWA’s scientists say there are already signs that the country’s climate is changing.

New Zealand’s climate varies naturally from year to year or even from decade to decade. However, it is the human-induced (anthropogenic) long-term trends, particularly the concentration of greenhouse gas in the atmosphere and the response of the global climate system, that will cause the climate that the country will be exposed to.

In New Zealand, the long-term increase in temperature has been around .90°C in the last century, just a bit below the global average.

Climate change projections from the 2016 report say that temperature and rainfall patterns in the years 2040 and 2090 will depend on the various emission pathways or amounts of emissions.

Projections of temperature in 2040 are as follows: In a low emission scenario, the temperature increase will be 0.7°C. A high emission scenario will produce a 1.0 °C increase in temperature. In 2090, low emissions will result in a 0.7°C increase in temperature, while high emissions will cause a 3.0°C temperature increase.

Emissions scenarios in New Zealand are aligned with the IPCC’s Representative Concentration Pathways (RCP). These four pathways, abbreviated as RCP2.6, RCP4.5, RCP6.0, and RCP8.5, are ordered according to the amount of greenhouse gas concentrations in the atmosphere.

RCP2.6 represents a low emissions and mitigation scenario wherein emissions stop after 2080. RCP8.5 represents a high-emission scenario or business-as-usual, and RCP4.5 and RCP6.0 represent two futures with global emissions stabilising at different levels.

What the climate future looks like will depend on which pathway we are on, the amounts of greenhouse gas emissions we are putting into the atmosphere, and the success or failure of mitigation efforts around the world.   

What will climate change look like in New Zealand according to the IPCC 5^th Assessment
Report?

• The average temperature will rise further if greenhouse gas emission continues
• Frost-free lands during spring and autumn will triple by 2080.
• An increase of up to 60 days of hot days or over 25°C temperatures for the northern areas by 2090
• A shift in rainfall patterns and rise in extreme rainfall of up to 8 per cent per 1°C of warming that will vary in some regions
• Droughts in the eastern and northern parts of the country will double or triple by 2040
• Global sea-level rise by 2100 will be about .5 to 1 meter in a high emissions scenario or 0.3 to 0.6 if there is rapid decarbonisation.
• The decline in peak snow accumulation is 30 to 80 per cent at 1000 meters and by about 5 to 50 per cent at 2000 metres by 2090.

How will New Zealand cope with climate change?

According to NIWA, New Zealand, as a temperate maritime country, may not face some of the worst effects of climate change this century, unlike parts of Australia, where peak temperatures of 40°C are projected to increase.

New Zealand is also generally well-equipped in principle to adapt to climate change, with some adaptation occurring already, particularly for sea-level rise. However, despite the country’s adaptive capacity, there are still some major constraints that need to be addressed, for example, limited integration of climate change in different levels of governance, a different attitude towards risk associated with climate change, and a few others (Climate change IPCC Fifth, n.d.).

Key Risks of Climate Change in New Zealand

NIWA highlights three risks New Zealand faces due to climate change. These risks were identified through strong and reliable research and because of the potentially severe impact on the country, which can make adaptation challenging (Climate change IPCC Fifth, n.d.).

1. Some communities are already experiencing coastal erosion from sea-level rise, which puts coastal infrastructure and low-lying ecosystems at risk. If future sea-level rise projections continue, which is predicted to happen by 2100, a coastal retreat is one possible solution.
2. Wildfire risk. According to NIWA, this risk is very high in Australia and a bit lower in New Zealand. Early warning systems, local planning mechanisms, and building designs, along with public education, can help with adaptation.
3. The increasing frequency and intensity of flooding can damage infrastructure and settlements. Planned adaptation measures include land-use control and relocation, protection, and accommodation of increased protection when feasible.