Is it getting warm in here? 30 January 2007

Chris Williams is taking climate change seriously

It is an unintended irony that the overall title of this section, referring to ‘Coalface’, has more to do with my topic this month than usual – coal being a fossil fuel, and the burning of fossil fuels, whether in cars or power stations, to generate energy said to be the primary cause of global warming.

Those of you who were astounded by the Western Cape’s recent high temperatures must have been asking if the environmentalists don’t have a point about global warming after all. I was spared the heat (I was attending a seminar for Masters of Wine students in Melbourne, Australia), but early reports are that it has had a big impact on sauvignon blanc flavour, as the iso-butyl-methoxy-pyrazine flavour pre-cursors in this variety are extremely heat-sensitive and prone to being ‘boiled away’ in the berry while still on the vine.

How appropriate then that one of my lectures in Melbourne was on climate change and the impact on viticulture. Note the words ‘climate change’ as opposed to ‘global warming’, for – in the magnificently complex homeostatic system that is the worlds’ climate – a mean global temperature increase may cause the average temperature of some areas to actually decrease. It has to do with the Gulf Stream, hyper-salinity of seawater and ocean mixing. However, that is about the whole sum of the good news.

I have been sceptical of the hype around climate change and remain so on specific causes, but being exposed to the evidence has opened my mind. The principle reason for global warming is the increase of ‘greenhouse gases’ in the atmosphere, mainly carbon dioxide. Since 1976, when the careful measurement of these parameters began (I was amazed it was so late) average atmospheric CO₂ has increased from 330 parts per million to 380ppm. In some places it is as much as 25 percent. Predictions are that, by 2100, atmospheric CO₂ will be up to 650 ppm. A significant group of scientists claim that this is a direct result of the burning of fossil fuels, either coal or oil. The increase will mainly result from the economic growth of China and India and their demand for energy.

I attended a lecture on how this would affect viticulture, both economically and qualitatively speaking. To summarise, all the effects will be negative, the degree will depend on whether we follow a worst case scenario or best case scenario. Best case scenario is that there will be a 7 percent negative impact on all the measurable parameters. Worst case is 57 percent negative impact.

The scientists also admit that they cannot fully predict the impact of all this excess CO₂ in the atmosphere. One oddly positive effect is that there will be more CO₂ in the atmosphere which will increase the rate of the carbon cycle  for green plants to bind CO₂ and turn it into biomass more quickly. There will be a higher carbon-to-nitrogen ratio in plant tissues and eco-philosophers claim this ‘gaia theory’ is the globe’s ability to adapt to changing circumstances. That will take extra water though…

Luckily for us in South Africa, some scientists claim we will experience minimal or no effects of climate change. Australia will be hardest hit but maybe that is simply global karma, considering Australia has the highest emissions of greenhouse gases per capita in the world….

Whatever the effects, I think the viticulturists, scientists and marketers are missing the point. If  the global temperature does increase, the knock on effects of melting polar ice-caps, conflict over water resources, declining food security  and population stress will be social and economic catastrophe. Hardly the conditions conducive to continue toasting our health  with chilled glasses of chardonnay.