Friday night’s ABC TV news contained a small segment on the likelihood of warmer winter weather for Australia’s ski-slopes. Apparently someone has done a study of the winter snowfall a hundred years ago, and is suggesting that snow falls were deeper then and the season lasted longer than is the case now. The two scientists interviewed seemed to be suggesting that we could look forward to more of this. I can’t at the moment lay my hands, or feast my eyes, on this report, which as a former skier I would read with interest. But the item stirred my interest in other ways.
That the ABC should have presented the report as newsworthy is not at issue. This year’s season was short, weak, and most disappointing to skiers, resorts and operators alike. A future like this would not be at all welcome. Neither of the men interviewed was asked why he thought these conditions would continue. There seem to me two possible answers, though the report may propose more.
The first is that conditions are generally warmer now than they were twenty years ago, when I was skiing a lot, let alone a century ago, and if you extrapolate from the last fifty years, then the trend is upwards. The second is that the General Circulation Models (GCMs) used by climate modellers project that this will happen. Neither of these possibilities seems very plausible to me. As I have pointed out in recent essays, the most recent trend is towards no further warming, or even cooling, and that possibility might have been offered to the scientists.
And the GCMs are not much good for regional outcomes, as the climate modellers have admitted. That is a major problem, because there is no modelling alternative. You have to start with the world, and then scale down to a region. Furthermore, the models vary widely in their capacity to project basics like temperature and precipitation for the world. When you apply their work to regions you can and do get opposite outcomes. You can see this problem in an account of a regional model for the Condamine Catchment in Australia:
The majority of the GCMs selected (80%) predict a decrease in mean annual rainfall. Four out of five models predict a mean annual rainfall decrease of 60-180 mm while one model (ECHAM), suggests a mean increase of about 60 mm for the period 2010- 2039. For the period 2040-2069, three of the GCMs selected suggest an overall decrease (60-180 mm) in rainfall while two of the five GCM models suggest an increase (60- 120 mm) in mean annual rainfall.
Which one should you rely on? Why any of them? The trouble is that local government bodies and state governments have to show that they are doing something in this area, so they ask around for expert help. We need to know what will happen, they cry. And there will always be someone who puts his or her hand up. Once they have the expert advice they start to tell us all what we will have to do. My response, if I were ever asked, would be to say that we don’t know much about the future save that it is ahead of us. But if you look at the regularities of the past, like floods, droughts and fires, you can be pretty sure that they will happen again. Why not start now adapting to that likelihood instead of pinning your faith on the output of unverified and unvalidated computer models? You see that I wouldn’t get very far — though we are beginning to hear about the need for adaptation to ‘climate change’, rather than mitigation, more frequently than was once the case.
Back to the skiers. The first piece of advice to them is this is not happening around the world. According to the Telegraph in London, ‘One half of North America’s largest ski area will open this weekend, thirteen days ahead of schedule. Whistler Mountain at Whistler Blackcomb will now open on Saturday, thanks to cold temperatures, intensive snowmaking and heavy snowfall. … A statement from Whistler said: “Thanks to oodles of snow, Whistler Mountain will open 13 days early this season. Whistler is renowned, season upon season, for being the number one ski resort for guaranteed snow – lots of it – and this winter will be no exception.” While I’m not suggesting that skiers cross the Pacific, it seems to be an early snow season at Lake Tahoe and in Maine as well.
What about Australia? If you search on the Internet for ‘snow depth in Australia’ you will get a lot of information over time. The most interesting I found was a forecaster’s site that did examine all the data, and projected possibilities up to 2030. It seems that the length of the ski season is strongly affected by large dumps of snow, which simply take longer to melt. When I was skiing we waited for the September ‘dump’, which would add weeks to the season for cross-country skiers. There wasn’t much of one this year.
His conclusion, using data that go back to the 1920s, is that the recent low levels of snow were matched between 1927 and 1953, and that levels will change from current Mean Trend of 170cms, back to a value nearer the Mean Trend of 1950 to 1974, which was 240cms (Values are all relative to Spencers Creek Hydro Data). It should be stressed that this does NOT, of course, infer that every year from 2010 to 2030 is forecast to be at that 240cms Trend Level… Only that Yearly Maximum Snow Depth Levels will be expected to increase to vary up and down around that new 240cms Mean Maximum Snow Depth Trend Forecast.
Well, there you go. I’ve no idea whether or not the forecaster is right. But if you look at the snow-depth diagrams, and there are lots of them, you can see that we get good years and bad years. My hunch is that there will be plenty of good years ahead for skiers, and I wish I were still one.