Greenhouse gas emissions from human activities are changing New Zealand’s climate, impacting the environment, communities, and the economy, according to  the latest, three-yearly update about the state of the country’s atmosphere and climate from the Ministry for the Environment and Stats NZ.

Our atmosphere and climate 2023 provides further evidence that emissions from human activities are putting pressure on the climate, which is adversely impacting the environment, communities, infrastructure and the economy.

The Ministry’s Deputy Secretary – Joint Evidence, Data and Insights Group, Natasha Lewis, says eight of the ten warmest years recorded in NZ up to 2022 have been in the last decade.

“Even minor changes in our climate can have big effects on our environment. Rising temperatures have a significant effect on agriculture, energy demand, ecosystems, and recreation,” she says.

The country is also experiencing variations in rainfall, more frequent droughts and ocean warming to record levels. Glaciers are in retreat and sea levels around parts of the country rose twice as fast in the last 60 years as they did in the previous 60 years.

The frequency of extreme temperature events in NZ has doubled due to human activities.

“This has consequences for the things we value most, our safety and security, the places we live, our livelihoods and economy and our wellbeing.”

About 750,000 New Zealanders and 500,000 buildings worth more than $145 billion are near rivers and in coastal areas already exposed to extreme flooding.

Major urban centres, sites of cultural significance, treasured species, and food security are also at risk in these areas.

“Many sectors of our economy rely on natural resources such as water, which depend heavily on rainfall and temperature or are in areas that are prone to flooding,” Natasha Lewis says.

“The cost of responding to extreme weather events is likely to increase.”

A key theme of the report is the impact that climate change is having on biodiversity and ecosystems. This natural infrastructure acts as a buffer against the worst effects of climate change. For example, restored wetlands can absorb the shock of storm surges and help to protect communities against sea level rise.

Native forests and restored floodplains reconnected to wetlands can slow and retain water during storms, helping to reduce flooding.

“Human activities are driving biodiversity losses,” Natasha Lewis says.

“It is now a question of how close we are to tipping points, beyond which large and, in some cases, irreversible changes will be unavoidable.”

Building on Our atmosphere and climate 2020, this report also includes a series of evidence-based assessments about the outlook for atmosphere and climate.

“Looking ahead, as well as behind, represents an important shift in our approach to environmental reporting,” Natasha Lewis says.

“We hope that this information helps people and organisations to understand climate change better and plan for the future.”

What is in the Our atmosphere and climate 2023 report?

The report brings together recently updated Stats NZ indicator data and insights from research literature to highlight pressures on the atmosphere and climate. These can cause, or contribute to, changes in the state of the environment, which have various impacts. Key insights from the report include:

Pressures

• Emissions from human activities put the most pressure on our atmosphere and climate.
• Our gross greenhouse gas emissions increased between 1990 and 2021, though they have remained relatively stable since 2006, despite increases in population and economic activity.
• In 2021, gross emissions further declined by 0.7 percent compared to 2020, largely due to decreases in emissions across the agriculture sector.
• The two largest contributors to our gross emissions in 2021 were the agriculture sector at 49 percent, and the energy sector (including transport) at 41 percent.
• Methane and nitrous oxide, largely from agricultural sources, made up over half of our gross emissions (43 and 10 percent respectively).
• The remaining emissions consisted mostly of carbon dioxide (45 percent), largely from Energy and the Industrial Processes and Product Use (IPPU) sectors.
• Our net emissions (total emissions plus any emissions added or removed by land use, land-use change, and forestry sector) increased by 25 percent between 1990 and 2021, due to the underlying increase in gross emissions.

State

• Annual average temperatures in NZ increased by 1.26 (± 0.27) degrees Celsius between 1909 and 2022 (114 years), with eight of the 10 warmest years on record in the last decade.
• Agriculture and horticulture growing seasons are lengthening, and frost days are declining in most places around the country
• Annual rainfall during the last 60 years has changed in most regions, with the south becoming wetter and the north and east becoming drier. Extreme rainfall is also changing in most places.
• The frequency of medium-term (agricultural) drought is increasing in many places.
• Extreme winds are decreasing at most sites, which may be due to a positive Southern Annular Mode (SAM)¹
• Extreme weather events are becoming more frequent and intense. The frequency of extreme temperature events in NZ has doubled due to human influence.

Impacts

• Annual mean coastal sea levels rose faster (relative to land²) between 1961 and 2020 than between 1901 and 1960 at all four longer-term monitoring sites around the country.
• Changing ocean currents and rising sea levels have led to a loss of nesting sites for various shorebirds and declining populations of sooty shearwater (or mutton-birds).
• The air-marine heatwaves in 2017/18 and 2021/22 caused bleaching and necrosis of sponges, mass mortality of little penguin in Bay of Plenty and widespread loss of southern bull kelp.
• Spatial mapping shows that sites which are of significance to Māori in Taranaki, Auckland, the Coromandel, northern Hawkes Bay, Tasman, and parts of Canterbury and Otago are at risk of coastal erosion.
• The Māori economy is particularly vulnerable to climate change because 50 percent of fishing quota, 40 percent of forestry, 30 percent of lamb production, 30 percent of sheep and beef production, 10 percent of dairy production and 10 percent of kiwifruit production is in Māori ownership.
• About 750,000 people and 500,000 buildings, worth more than $145 billion, are near rivers and in coastal areas already exposed to extreme flooding.
• Treasury estimates that the cost of repairing damage caused by Cyclone Gabrielle and the Auckland floods in 2023 to be between $9-$14.5 billion.

Outlook

• It is highly likely the world will not meet Paris Agreement long-term goals of limiting global temperature increase during the 21st century to well below 2 degrees Celsius above pre-industrial levels.
• It is highly likely that NZ will experience increased temperature and changing rainfall patterns until 2050 and that extreme weather events will become increasingly frequent and severe.
• It is almost certain that climate change will continue to increase risk to the country’s native and endemic species.
• It is highly likely that climate change will continue to adversely impact our infrastructure and communities, threatening our wellbeing, connection to place and livelihoods.
• It is highly likely that health and wellbeing outcomes will deteriorate because of climate change and biodiversity loss, including the introduction of infectious diseases and food insecurity.
• It is highly likely that climate-related impacts will displace Māori in some places, disrupting the transmission of location-specific mātauranga Māori and tikanga practices.

The report is available at Our atmosphere and climate 2023.

Stats NZ’s atmosphere and climate indicators are available at Selected environmental indicators (atmosphere and climate): Data to 2022.

Source:  StatsNZ