Drought lengthened by climate change

The evidence is in - humans have left a distinctive fingerprint at the 2013 drought crime scene.

In an international paper released this week, New Zealand scientists have analysed climate models around the extreme weather event, which knocked at least $1.3 billion out of New Zealand's economy.

While the natural variations played a leading role, human activity was a definite accomplice, according to National Institute for Water and Atmospheric Research scientist Sam Dean.

With two Victoria University and two fellow Niwa scientists, Dean used computer modelling to compare the 2013 climate over New Zealand with a simulation of the world "that might have been" without the greenhouse gases and chlorofluorocarbons that people have pumped into the atmosphere.

"We found that the drought was a little more intense than it would have been without climate change."

In summer, greenhouse gases and the ozone hole intensified the high-pressure systems that brought dry weather, Dean said.

The models showed climate change added several extra dry days to the average total of 78 during which there was no rainfall in the North Island last year.

"Climate change is making a difference to New Zealand now, affecting our droughts and our rainfall extremes."

Last year's rural assistance bill topped $800,000.

Climate Change Issues Minister Tim Groser declined to be interviewed but said in a statement that New Zealand was in a good position to adapt to its changing climate. "The Government has advice out there for businesses, particularly farmers, to help them with that."

But Green Party climate change spokesman Kennedy Graham said the Government was paying little more than lip service to reducing greenhouse gas emissions.

The Federated Farmers vice-president, Anders Crofoot, said the stress of last year's drought was still being felt on North Island farms.