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.
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.
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.
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 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.
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.