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 37.1 °C (Neilson, 2020).

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

On 2 February 2020, Newshub also reported temperatures of over 35°C around the country, with fears that they could rise above 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What used to be the cool seas in the north of Australia have been replaced by warmer seas, which cause a rising motion in the Atmosphere, creating rain and thunderstorms, says NIWA meteorologist Ben Noll on Hub news (Palmer, 2020).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 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 5th 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 states that climate change is caused by increasing amounts of greenhouse gases in the atmosphere. In New Zealand, changes in key climate parameters, such as temperature and rainfall, are already being felt.

Climate change projections are not expected to occur this year or in the next few years, but rather 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 gases in the atmosphere and the response of the global climate system, that will determine the climate to which the country will be exposed.

In New Zealand, the long-term increase in temperature has been around 0.90 °C over the last century, just slightly below the global average.

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

Projections of temperature in 2040 are as follows: In a low-emission scenario, the temperature increase is expected to be 0.7°C. A high-emission scenario will result in a 1.0 °C temperature increase. In 2090, low emissions are expected to result in a 0.7°C temperature increase, while high emissions are projected to 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.

The climate future will depend on the pathway we are on, the amounts of greenhouse gas emissions we are releasing into the atmosphere, and the success or failure of mitigation efforts worldwide.   

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

• The average temperature will continue to rise if greenhouse gas emissions persist.
• Frost-free lands during spring and autumn are expected to triple by 2080.
• An increase of up to 60 days of hot weather or over 25°C temperatures for the northern areas by 2090
• A shift in rainfall patterns and a rise in extreme rainfall of up to 8 per cent per 1°C of warming, which 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 approximately 0.5 to 1 meter in a high-emissions scenario or 0.3 to 0.6 meters if there is rapid decarbonization.
• 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 already occurring, particularly in response to sea-level rise. However, despite the country’s adaptive capacity, there are still some significant constraints that need to be addressed, for example, the limited integration of climate change into different levels of governance, a different attitude towards the risks 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 due to 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 seaside 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, as well as protection and accommodation, where feasible.