29 Jan 2019

Weather study provides glimpse of future climate change

From Nine To Noon, 9:08 am on 29 January 2019
Thermometer on the summer heat

Photo: Science Media Centre

New analysis examining the impact of last year's heatwave on Dunedin and the South Island, is carrying stark warnings for the future.

The effects were numerous: Sub-tropical fish species not usually seen around Dunedin, such as Kingfish, were caught by Port Chalmers fishermen, and as far south as Bluff, in numbers unheard of, the kelp that provides habitat for other fish and marine species died off; farmed salmon failed to thrive - and even surfers could wear board shorts instead of wetsuits.

The analysis of atmospheric and oceanic data sets by scientists from Victoria University of Wellington, NIWA, the USA's National Oceanic and Atmospheric Agency, the University of Otago and the University of New South Wales revealed the "unprecedented" combined ocean-atmosphere heatwave was driven by the dual effects of warm atmospheric air and low wind speeds, which would usually have a cooling effect on the sea.

The collaboration was led by climate scientist Dr Jim Salinger who talks to Kathryn Ryan.

The combined annual New Zealand land air (NZT) and sea surface temperature (SST) record, in °C, compared with the 1981-2010 average. The blue bars represent individual years, and the red line trends over groups of years.

The combined annual New Zealand land air (NZT) and sea surface temperature (SST) record, in °C, compared with the 1981-2010 average. The blue bars represent individual years, and the red line trends over groups of years. Photo: Dr Jim Salinger