Environment Southland working with other regional authorities to prepare

New Zealand is taking the issue of climate change seriously.  Yvonne O’Hara, in the final part of a special report with the assistance of the  Aotearoa/New Zealand Science Journalism Fund, looks at the predicted impact it will have on the environment, infrastructure and future  generations in Otago and Southland.

Environment Southland (ES) knows what is coming and is making plans. ES senior policy planner Gavin Gilder said Southland was expected to have gradual changes in climate during the next 100 years and was working towards a collaborative approach with other authorities in the region to adapt.

Ministry for the Environment data showed the Southland environment was predicted to be drier and warmer, with fewer frost days as well as more rain and wind and more frequent extreme events.

He said there could be fewer snow days, less snow and less snow melt, which would affect surface water recharge.

"That will have implications for minimum flows and seasonal water availability. On the other hand that will mean better grass growth, as well as higher temperatures and [it] will probably be wetter.

"Then there will be more opportunities for pest plant species to establish in areas where it had been too cold to survive previously — think velvet leaf."

Another concern is the anticipated sea-level rise of about a metre in the next 100 years, worrying for low-lying and coastal areas, such as Riverton and Colac Bay.

Any land lower than 3.5m  above mean sea level was considered to be at risk in the near term and, looking 100 years ahead, there was some risk for land up to 5m above mean sea level.

Flood protection would be increasingly important and stopbanks surrounding Invercargill and its estuary should be re-evaluated to determine if they needed to be raised further, particularly as the sea had already over-topped them last year.

The Southland District Council recently initiated a review of how climate change was predicted to affect the region.

Mr Gilder said a priority was better modelling for floods, tsunamis and other events.

He wanted to use a better digital elevation model over the region to look at which areas were likely to be affected, such as flood plains, and which needed to be prioritised.

There would be a four-fold reduction in the time between 100-year flood events and, as well, by 2090 to 2100, there would be more frequent and intense events.

"The rate of change we will see is related to the amount of carbon emissions and there has to be a significant change in those."

Environment Southland’s website says Mataura,  Gore and Riversdale as well as the Wendon, Nokomai and Lumsden areas seem to have suffered the most from very heavy rain and hail as well.  

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