WHAKAPAPA Sky Waka depends heavily on the seasonal trade from skiers. PHOTO SUPPLIED
King Country News sent some questions on this phenomenon to weather and climate researcher James Renwick, who is a professor of physical geography at Victoria University of Wellington:
Q. Central North Island tourism operators used to recite a rhyme to remind themselves of when the ski season would begin:
“Snow in May – won’t stay Snow in June – too soon Snow in July – you can rely”
Q. So, how might the advent of global warming change this way of predicting snow in the years to come?
A. Climate change is shortening the snow season, pretty much everywhere. The first snows are coming later and the last snows earlier. So, the “July – rely” rule of thumb will become less reliable as time goes on.
Q. Are we likely to receive more rainfall in the Central North Island due to climate change, and if so, how could this affect ski fields? Is the additional rain which we understand is predicted to be part of increased global warming, likely to fall on the mountains in our area as water or snow?
A. The central North Island is likely to get more precipitation in winter, with not too much change at other times of year. But when it rains, there’s more likely to be heavy rain, as the air holds more moisture as it warms. If surface temperatures are below freezing, the precipitation will be snow, otherwise it’s rain. As temperatures rise, the balance gets tipped more and more towards rain and away from snow. But snow will still fall in the mountains for a long time yet, even though it’ll be less frequent.
Q. As you will be aware much has been written recently about French ski resorts being forced to dismantle ski tows as climate change reduces snow. Is this likely to have an equivalent effect in the Southern Hemisphere generally, and in particular in the Central North Island?
A. Yes. The same forces are operating in New Zealand as in France and elsewhere. As the climate warms, “cold pursuits” like skiing become more and more marginal, and less economically viable.
Q. These articles also tend to mention an apparent “greening” of the Alps. It is said climate change may reduce alpine snow cover and increase vegetation productivity, as in the Arctic. Do you see the same sort of changes in New Zealand . . . meaning plant life changing on the alpine slopes of Ruapehu and its mountain companions?
A. Probably, but I haven’t read of any work on this here. It’s a reasonable expectation though.
Q. Any additional thoughts on aspects of climate change concerning the mountains of the Central Plateau.
A. Climate change will fundamentally change alpine environments, and environments generally. Less snow and ice, more variable rainfall (more floods, and droughts), and higher temperatures will make the Central Plateau a different environment to what it has been. Vegetation will change as the climate warms, so we’re likely to experience quite a different “feel” to the region as the climate continues to change. I personally think that’s quite a hard thing to take on board. The emotional response to all of this is hard.
