editorial

 

Leonie Joubert

The winter of 2007 felt brutal: severe flooding drove many from their homes across the Cape Flats and even parts of Cape Town’s southern suburbs were sump-deep in runoff; repeated snowfalls over many parts of the country, including the first in Gauteng since September, 1981, and Pretoria since June, 1968; some Free State maize farmers reported the worst frosts seen in three decades, if not more. Global warming? Yeah, right!

Well, there’s an explanation, because it turns out there’s a big difference between once-off weather events – or a winter full of them – and climate. “Weather”, according to my Oxford dictionary, refers to “the state of the atmosphere at a place and time as regards heat, cloudiness, dryness, sunshine, wind, and rain etc”. That means that whatever the atmosphere is doing around your city, for instance, at a specific time, can be measured according to those attributes.

“Climate”, on the other hand, is the combination of all those aspects of weather in a place, from which trends will emerge over a long period of time. One August day in Cape Town, for example, may be sunny and mild even though we know that the climate for the city puts it in a winter rainfall region. Weather is notoriously chaotic and therefore difficult to predict more than a few days in advance – which is why we curse the local weatherman for not getting it spot on for Saturday’s cricket. This, says the United Nations expert climate group, the Intergovernmental Panel on Climate Change (IPCC) in its Fourth Assessment Report, is the cause of much of the confusion around this subject in the popular mind.

Many sceptics of climate change have rightly asked just how one could possibly predict what our climate will be like in 50 years from if meteorologists can’t even predict the weather accurately a fortnight from now. This is easily explained by a lovely IPCC analogy, cherry picked out of the hefty thousand-page tome released earlier this year: “… while it is impossible to predict the age at which any particular man will die, we can say with high confidence that the average age of death for men in industrialised countries is about 75”.

It is much easier to stand back and look at decades of weather records and see trends in climate emerge from them than it is to predict whether it will be sunny or overcast somewhere beyond more than about ten days from now.

“Another common confusion of these issues,” states the IPCC, “is thinking that a cold winter or a cooling spot on the globe is evidence against global warming. There are always extremes of hot and cold, although their frequency and intensity change as climate changes.” Typical of the South African condition, this year’s rough winter came on the rapidly retreating heels of one of the worst droughts to hit the region in 40 years or more. Extreme weather events have carved out the natural landscape in South Africa. Now, say climate change modellers, rising atmospheric greenhouse gases will bring increasing temperatures across our country. This will amplify the natural cycles, bringing heat waves, droughts and floods with more frequently and with greater intensity.

If the old adage says that weather is only good for small talk, then it needs updating. Weather, these days, is good enough for the daily headlines.

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