Central Otago's weather forecast to get extreme

Scientist Chris Cameron (pictured) who with other members of the Bodeker Scientific team, of Alexandra, has written a report about climate change implications in Central Otago. Photo / Yvonne O'Hara

Sweltering temperatures, floods and storms could be Central Otago's future.

New research predicts that by the end of the century the district will be warmer and wetter with more extremes, including flooding, wildfires and storms, and there will be far less snow cover on the mountains than at present.

Scientist Chris Cameron, of Bodeker Scientific, said those changes would cause flow-on issues for irrigation, horticulture and viticulture, and was likely to influence the number of people wishing to move to the region.

The Alexandra-based company was commissioned by the Central Otago District Council to look at the impacts climate change would have on the region, as part of its long-term planning and to generate discussion.

Mr Cameron was one in a team of scientists who researched the issue.

The report, to be discussed by Central Otago councillors next week, said the district's temperature was likely to increase by several degrees, with much less snow, by the end of this century.

The annual total rainfall was not predicted to change much district-wide, but the intensity of rainfall would increase and there would likely be more extreme rainfall events.

The changing profile of rainfall throughout the year, as well as less water being locked away as snow until spring, meant less water available for irrigation and storage as well as knock-on effects for river flows (including minimum flows).

"I was interested to see there was the potential for snow cover to be effectively gone (from Central Otago) by the end of the century," Mr Cameron said.

"That is a consideration for irrigators and the Otago Regional Council around water allocation."

In addition, Mr Cameron said there were likely to be about 53 fewer frost days, which was about half that experienced now.

Summers would be longer and warmer, with up to 64 more summer days, about double the present number, depending on location. Maximum temperatures would be up to 5.8degC warmer.

Winters would be warmer by between 2degC and 4degC, compared to 2009 data, and some areas would have no spring or autumn frosts.

Infrastructure such as stormwater drains and roading could be affected by the heat and the extra water volumes, while stock and people might experience heat stress.

Mr Cameron said the changes could mean, by the end of the century, farmers would be planting different crops that were faster maturing, and horticulturists might have to change their management systems.

There could be an increased demand for water for drinking and irrigation. Many pests and diseases would thrive.

He said higher sea levels as a result of climate change could mean more people would move to Central Otago from coastal areas, so there would be an increase in demand for housing.

He said there was a lot of research being carried out to make people more aware of the issues and around how to adapt.