Jim Renwick takes a cold view of a hot topic

Lying down on the job, Jim gets up close and personal with Antarctic conditions.

Jim Renwick is one of NIWA’s climate scientists, based in Wellington. When we spoke to Jim last month, he had just returned from Antarctica. Swapping survival suit for dinner jacket, he received a prize at the Royal Society’s formal awards dinner – the Meteorological Society’s Kidson Medal for the outstanding scientific paper on a weather/climate topic. Jim’s paper was on links between Antarctic sea ice and El Niño.

W&A – You're saying the climate in the tropics affects Antarctica?

Jim – El Niño and La Niña are driven by the tropical Pacific Ocean, and their influence extends outward from there. Ten years ago, no one thought El Niño could affect Antarctica, but it does. During El Niño years, we see more big highs staying longer over the southeast Pacific. The result is less sea ice in the South Pacific but more in the Weddell Sea and South Atlantic.

This year, I got a grant from the Marsden Fund to look at links between El Niño and the ozone hole. I think El Niño may help explain why the ozone hole breaks up really early sometimes, because El Niño affects the westerly winds which keep the hole in place.

W&A – With climate change, what will life be like here in 50 years' time?

Jim – New Zealand’s climate will probably get a bit harsher: the winds will get stronger, wet areas will get wetter, dry areas will get drier. It won't happen overnight and farmers will adapt. For city dwellers, energy will be the big issue (see Jim’s article on climate variability). We'll want more electricity than now to cool our houses in summer and less to heat them in winter, but maybe the lake levels will be more constant, which would be good news.

W&A – How did you get interested in science?

Jim – I grew up in Springfield, 60 km west of Christchurch. According to publications at the time, the town had a population of 337. Partway through primary school, we got a new headmaster, Mr Bird, from the Bay of Islands. He bought some chemistry gear and weather-observing tools, and that really got me interested. At secondary school I took maths, physics, and chemistry. During my maths degree at Canterbury University, I discovered I really enjoyed fluid mechanics, which is important for studying the weather and climate.

W&A – How can the air be a fluid?

Jim – A fluid is simply any substance that flows, so gases can act as fluids. The wind is a fluid flow, moving heat from the tropics towards the poles.

W&A – You started out as a weatherman?

Jim – I was recruited into the MetService. After a year of training, I worked on aviation and marine forecasts. I'd read my forecasts live on National Radio at 4 am for boaties. The forecasts were very formal because they are so important for safety. The aviation ones were also very specific, and had to be updated at least every 3-4 hours. You had to forecast wind speed and direction, the height of each cloud layer, the amount of cloud in each layer, precipitation, and visibility. You'd be doing 20-30 airport forecasts several times over on your shift.

The group I was with at the MetService also did research. I did a Masters part-time at Vic, then went to the US for my PhD. While I was there, during the restructuring of the early 90s, our MetService group joined NIWA.

W&A – What’s the farthest out you've ever had to forecast?

Jim – At NIWA, I help produce the seasonal climate outlooks. If you think it’s hard to forecast tomorrow’s weather, try predicting the climate over the next three months! I once forecast the weather for New Year’s Day 3000 for a newspaper’s millennium (Y2K) special.