Wake-up call for NZ in climate report

23:29, Mar 31 2014

New Zealand must take its head out of the sand and adapt to sea-level rises, droughts and storms that will come with climate change, a leading scientist warns.

Professor Tim Naish, speaking after the publication yesterday of the second part of the United Nations Intergovernmental Panel on Climate Change's Fifth Assessment Report, said New Zealand had to ''futureproof'' for coming generations.

''This report is a wake-up call for New Zealand to take its head out of the sand.''

The second part of the United Nations Intergovernmental Panel on Climate Change's Fifth Assessment Report was released yesterday.

The chapter on Australia and New Zealand predicts a rise in temperatures of 2 degrees Celsius to 4 degrees celsius, increase in temperatures, more common heavy rainfall, frequent floods, increasingly common droughts and heightened bushfire risk in parts of New Zealand.

Professor Tim Naish, director of the Antarctic Research Centre at Victoria University, said the country had to ''future proof'' for coming generations.


By 2100, the country could see floods previously regarded as ''one in 100 year'' events happening annually. 

In the South Island, the wet will get wetter and the dry will get drier, but there could be benefits in increased river flows from the Southern Alps, the report says.

National Institute of Water and Atmospheric Research principal climate scientist Dr Andrew Tait co-authored the chapter on New Zealand and Australia in the second part of the fifth United Nations Intergovernmental Panel on Climate Change (IPCC) assessment report.

Tait said westerly airflow ''ramping up over time'' would bring more rain to the south and west of the South Island.

Westland, Otago and Southland could receive a 10 to 15 per cent increase in annual rainfall. But those westerly winds would exacerbate the rain shadow that dries out the east coast, including Canterbury, meaning less rainfall for the east and northeast of the South Island.

Victoria University climate scientist Dr James Renwick said the projected rainfall for the country was ''no different to what's been said over the last few years''.

''Those messages are very much the same as they were in the last IPCC report. The basic picture hasn't really changed that much.'' 

Warmer temperatures could also increase the frequency of drought across the country.

Increased rainfall on the mountains would have flow-on effects to rivers. The large Canterbury rivers, with headwaters in the Southern Alps, are driven mostly by spring snow melt.

With increased rain on the Alps, and snow melting earlier in the year, the Clutha, Waimakariri and Rangitata rivers could have a flow increase of between 5 and 10 per cent.

Tait said less snow would limit the spring pulse of river flow, but could mean more reliable flows in those rivers across the seasons.

Renwick said increased flow in those rivers could imply more water availability, ''which could be a sort of swings and roundabouts situation'' since it would probably accompany increased dryness, and therefore demand for water, in the east.

The report also said there could be an increased potential for winter hydropower in the South Island.

Prime Minister John Key noted New Zealand contributed 0.2 per cent of world emissions.

''In the end, we can only do so much and that's actually a pretty small amount on our own.''

The country has 0.06 per cent of the world's population of 7 billion, according to Statistics New Zealand.

The Press