2018 was NZ’s hottest year, claims scientist

Climate scientist Dr Jim Salinger says 2018 was the warmest year on record in New Zealand. He’s making the call ahead of the official analysis of last year’s weather, expected from Niwa next week.

The year started with the country’s warmest ever month. As a result of more northerly winds and higher than normal sea surface temperatures, the mean temperature was 20.3 degrees Celsius in January 2018.

Based on Niwa’s seven station series, which started in 1909, that was 3.1C higher than the January average from 1981-2010. Salinger said he calculated that the mean annual temperature for all of 2018 was 13.5C – or 0.85C above the average for 1981-2010.

Niwa figures – excluding 2018 – show 2016 was the warmest year on record with an annual mean temperature of 13.44C – 0.84C above the 1981-2010 average.

Until Niwa includes the 2018 figures in the record, 2017 is ranked as New Zealand’s fifth warmest on average.

Salinger said six of the months in 2018 had temperatures about 1C, or more, above average. ‘‘We had lots of warm months, no cold months, and a couple of average months. When you add that all up, it pushed us to the highest year ever for New Zealand.’’

Global heating was one of the main reasons for the warmth, while another factor was the large ‘‘blobs’’ of warmer than usual water around the country. Some areas of warmer water remained, more around the South Island.

‘‘So it wouldn’t surprise me if more snapper are caught in the far south, as they were last year,’’ Salinger said.

Niwa principal scientist – forecasting Chris Brandolino said the plan was for Niwa to publish its climate summary for 2018, including temperature data, next Tuesday.

An analysis was still under way, and for now all he was able to say was that 2018 was very close to 2016 in terms of the temperature anomaly, or difference from average.