Thursday, September 11, 2014

Climate Change: Unsettled science or pointing the bone?

Wikipedia says that ‘moral panic’ occurs when an issue or situation becomes defined as a threat to social values and interests. There is no doubt that climate change falls in the dead centre of moral panic, whether you are a believer or a non-believer.

There is no better illustration than the August 2014 Australian Grapegrower and Winemaker magazine. Blaring from its front cover are the words ‘Climate crisis: special news feature.’ There are 13 pages on the subject in the magazine, most of which trot out the conventional arguments of those screaming from the rooftops about the immediate crisis.

By far the most interesting was a report on the Australian Wine Research Institute’s Dr Mardi Longbottom, who currently manages research and extension projects focused on greenhouse gases (CHG) and sustainability in the grape and wine sector.  She points out the global warming potential of nitrous oxide is around 300 times that of carbon dioxide, and that its contribution to global warming is significant even though its volume is small.  The AWRI has been working on a project investigating N2O emissions from vineyards, and preliminary results of the experiments show the N2O emissions from Australian vineyards are similar to those measured in Californian vineyards, and are very low compared to other horticultural crops.  Moreover, reducing N2O emissions of anthropogenic origin (soils release low levels of N2O regardless of any agricultural activity or soil enrichment) is relatively easy.

When you come to CO2, the plants, grasses and trees exist on earth only because of the availability of their food source, CO2. Vineyards are very effective in making use of CO2, particularly in a warming climate (let’s not get caught up in the fact that the globe has not warmed since 1997), but there are undeniable shifts in climate.

Dr John Gladstones points out that long-term commercial greenhouse practice shows that yield can increase without any loss of quality if there are enhanced CO2 levels linked to higher temperatures.  Taking this knowledge to the vineyard, autumn cropping, and winter pruning means a low carbon status in spring, and a need for the vine to utilise CO2 to maximise root growth, canopy growth and fruitfulness.  Increasing levels of CO2 should allow vines to carry higher yields, while remaining in carbon balance.  There should also be sufficient surplus assimilate to ripen the current crop, and promote continuing root growth through the ripening phase.  In addition, enhancing the vine’s water use efficiency should improve its stress and growth balance in environments previously too dry and stressful, and thus extend viticulture into regions with lower rainfall at fruitset and subsequent ripening.  The question then is, how great an increase in CO2 will be relevant and beneficial?  Greenhouse horticultural crops grown in an environment between 700 and 900 ppm CO2 need temperatures 2˚C to 4˚C higher than normal atmosphere to fully achieve enhancement yield and quality potential.

This leads to Dr Gladstones’ conclusion in his book Wine, Terroir and Climate Change, at page 199:

‘I conclude that the widely held expectation of a viticultural flight to existing cold areas is misplaced. Optimum locations for particular wine styles will probably change little over the coming half century. Any minor shifts will be into areas with higher actual or effective night temperatures, eg closer to coasts, to warmer soils or to slopes with superior night air drainage. Favoured sites in warm to hot climates will have higher afternoon relative humidities, most desirably from afternoon sea or lake breezes.’

Looking at the broader picture, Bjorn Lomborg, adjunct professor at the Copenhagen Business School, is one of those who does not dispute that in the longer term, the earth is warming, but most certainly says there is no cause for panic.  He and others have made the following points:
·      The International Energy Agency (IEA) says that in 2010 the world derived 0.7% of its energy from wind and 0.1% by solar. In 2035 (with an optimistic green scenario) the IEA forecasts 2.4% wind and 1% solar energy. On the other side of the coin, and with identical time parameters, fossil fuel energy will only fall from 81% to 79%.

·      Globally, cold is a far greater contributor to deaths than heat. By mid-century researchers estimate there will be 400,000 more heat deaths, but 1.8 million fewer cold deaths. (Based on median IPCC forecasts of global warming.)

·      Since 1900 warming has resulted in a net economic benefit of 1.5% of GDP per annum. The benefit will peak about 2025, and it won’t be until towards the end of the century that net gain will turn into net loss (accepting the IPCC projections on warming through the century).

·      The EU 20-20-20 policy, which aims to cut greenhouse gas emissions to 20% below 1990 levels by 2020, and ensure 20% renewable energy supply, costs about $250 billion a year. By the end of this century, its cumulative cost will be $20 trillion, yet on a standard climate model it will have reduced global temperature by a mere 0.05˚C.

·      If nothing is done to control warming, the cost over the next 200 years is estimated to be $33 trillion, but GDP will run to $2200 trillion. Thus warming will cost 1.5% of GDP.

·      The percentage of emissions from all developed nations has, in fact, continued to fall since 1990, but those from Asia, and from Africa, Latin America and the Middle East have risen dramatically. It is expected these will peak about 2050 before falling somewhat by 2100, when they will account for around 60% of total emissions.

·      Kyoto set a target of 36.6% rise in global emissions from 1990 to 2010. In fact they have increased by 45.4%. With no Kyoto, the increase would have been 45.9%. Thus 20 years of discussions have had next to no impact, and the cost of implementing more stringent controls will far exceed the economic benefit of present green/renewable technologies.

What, then, to make of all this?  West Australia, led  by Margaret River, has had a succession of outstanding vintages from 2007 through to 2014.  For most in South Australia, 2012 was one of the greatest red years for many decades; indeed, Grant Burge poses the question: Best ever?  2010 was another truly great vintage, ‘09 very good.  The missing vintage?  Well, it certainly wasn’t affected by heat, just lots and lots of rain.  Southern and central Victoria followed in the same pattern, adding 2013 to the marvellous 2012 vintage.  And 2011 was absolutely outstanding for chardonnay.  What about the Hunter Valley?  It had a marvellous 2011 as the rain clouds parted and swept around it as they came down from the north; 2012 was typical with vintage rain (nothing new there) but 2013 was primed to be called the vintage of the decade until 2014 came along, said by those with long memories (or good cellars) to be the best red wine vintage since 1965.

Crisis?  I don’t think so.

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