Evidence of climate change

The changes in our environment and what they tell us about climate change.

It’s getting hotter in New Zealand and around the world

The average temperature in New Zealand has risen by 1.3 degrees Celsius since 1910 (when we first started recording climate information).

Evidence suggests that it has been about 10,000 years since the average annual temperature in New Zealand has been this high.                  

The warming observed in New Zealand is consistent with warming around the globe. Worldwide, in 2018 recorded temperatures have risen by 1.0 degrees Celsius.

1.0 degrees Celsius may not sound like a big increase, but it is a part of a much larger problem.

Today’s climate is only 2-7 degrees different from the climate during the last ice age (when large parts of Europe and North America were covered in ice). So changes that seem small can have major consequences.

Find out more in Our atmosphere and climate 2020 report.

Figure 9. Graph.
Graph showing temperature by year and decade between 1910 and 2019. 2010–19 was New Zealand’s warmest decade on record.
Figure 9. Graph.
Graph showing temperature by year and decade between 1910 and 2019. 2010–19 was New Zealand’s warmest decade on record.

Glaciers are melting and sea levels are rising

Hotter weather has begun melting glaciers and warming the oceans – triggering rising sea levels.

The global mean sea-level rose by 7 centimetres in just 25 years. Some seaside cities around the world are already losing their coasts to rising sea levels.

In New Zealand, coastal flooding due to sea-level rise has put more than 330 Department of Conservation sites at risk.

flood image
A flood affecting roads, farmhouses and paddocks.

Image: Alan Blacklock, NIWA

Oceans are warming and becoming more acidic

From 1981 to 2018 water around New Zealand’s coast has warmed by an average of 0.2 degrees Celsius per decade.

Higher concentrations of carbon dioxide in the air is dissolving in the world’s oceans and making them more acidic. Ocean surface water has become 26 per cent more acidic since the beginning of the industrial era. 

Find out more in Our atmosphere and climate 2020 report.

Seasons are changing

New Zealand’s seasons are changing, creating warmer winters and record hot summers. 

Find out more in Our atmosphere and climate 2020 report.

Rainfall is becoming less predictable

Some areas of New Zealand are experiencing more rainfall while other areas are experiencing significantly less.

Find out more in Our atmosphere and climate 2020 report.

Frosts are becoming less common

A frost day occurs when the minimum air temperature is below 0 degrees Celsius. Because our climate is not as cool as it used to be frost days are happening a lot less frequently in many places.

Dry spells and droughts are becoming more frequent in many places

Dry spells are becoming more common especially in the North Island. Auckland experienced its longest dry spell in early 2020, which finally ended after 47 days.

In comparison, the average length of dry spells in Auckland between 1960 and 2019 was just 10 days. 

Find out more in Our atmosphere and climate 2020 report.

The risk of wildfires is changing

Many countries are experiencing an increase in wildfires due to hotter, dryer weather. 

In New Zealand there are some sites that regularly have high number of days per year with very high or extreme fire risk.

For example from 1999-2019, Tara Hills, Lake Tekapo and Blenheim all averaged at least 28 days per year of very high or extreme fire danger.

Find out more in Our atmosphere and climate 2020 report.

A large wildfire at night, with red smoke above the hills.
A fire on the Port Hills in Christchurch on February 2017.

Image: Mark Hannah Photography.

A large wildfire at night, with red smoke above the hills.
A fire on the Port Hills in Christchurch on February 2017.

Image: Mark Hannah Photography.

How climate change affects us

Some of these changes are already affecting us in negative ways. 

Find out more in Our atmosphere and climate 2020 report

Find out more about how climate change affects New Zealand

Find out how climate change affects Māori

More about climate change