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​Climate change is happening now

​The climate is warming, which has and will continue to result in means a number of changes to temperature, rainfall, drought, snow, wind and sea-level in New Zealand. 

Changes that have already occurred include:

  • ​An overall warming trend: nationally averaged temperatures have increased by about 0.96°C between 1910 and 2010.

tait-Cs_fig1.jpg
Mean annual temperature for New Zealand, calculated from NIWA's 'seven-station' series. This series uses climate data from seven geographically representative locations. The data are adjusted to take account of factors such as different measurement sites. The blue and red bars show the difference from the 1971-2000 average. The black dotted line is the linear trend over 1910 to 2010 (0.96°C/100 years).

  • Fewer frosts over most of the country: Canterbury and Marlborough, for example, experienced about 20 fewer frosts per year in the early 2000s than in the early 1970s.

  • Retreat of major South Island glaciers: the volume of ice in the Southern Alps reduced by almost 11% in the past 30 years.  Twelve of the largest glaciers are unlikely to return to their earlier lengths without extraordinary cooling of the climate.

  • In December 2011, an unprecedented rainfall event occurred in Golden Bay and Nelson.  The township of Takaka recorded 674 mm of rainfall in 48 hours – the largest 48 hour accumulation of rainfall ever recorded in an urban area in New Zealand.  Analysis of this event indicates that the total moisture available for precipitation may have been 2-7% higher as a result of the emission of anthropogenic greenhouse gases.

  • Sea-levels have risen 0.16m during the 20th century averaged over the four main ports.

There is now strong evidence that the cause of the observed warming cannot simply be natural variation. 

In its Fifth Assessment Report (AR5), the Intergovernmental Panel on Climate Change (IPCC) states with 95% confidence that humans are the principal cause of current global warming.  This is known as anthropogenic global warming (AGW), and is primarily caused by the increase in greenhouse gas concentrations in the atmosphere resulting from human activity.

 

  

​​Key Messages

Temperatures set to rise

Air temperatures are projected to increase by about 1°C by 2040 and by 2°C by 2090 for a mid-range scenario.  The full range of projections across scenarios is 0.2-2.0°C by 2040 and 0.7-5.1°C by 2090... read more

Rainfall - drier in the east, wetter in the west

The overall projection is for 5-10% less rain in most of the east coast and north of the North Island, coastal Canterbury & coastal Marlborough, and for a wetter climate in the west and south of the South Island by the end of the century. read more

Drought frequency and length will increase

The most likely scenario sees farmers in most North Island regions, as well as those in eastern regions of the South Island – especially Canterbury and eastern Southland – spending 5-10% more of the year in drought by the middle of the 21st century. read more

Snowfall reduction

It is likely that average snowlines will rise as the temperature increases.  read more

Strong winds

An increase in frequency of extreme winds in winter is expected across most of the country, but especially in Wellington, Canterbury, Otago and Southland.  read more

Sea-level rise

Sea levels will continue to rise over the 21st century and beyond, primarily because of thermal expansion within the oceans and the loss of ice sheets and glaciers on land.  read more

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