Whether global warming is fact or fiction there is a definite feeling out there that the 2010 summer-Australian vintage 2010 is going to be a warm one.

The first indication of this alarming reality is to take a view of the average winter temperature for the Australian continent in 2009. It is up 1.76 oC on the long term average, and the second hottest winter in the past six years. That spells out that the 2010 season is going to break early with many regions of the country bursting with buds (chardonnay is usually the first) early in September.

Darling Downs viognier

Just in case the grapes were planning to be sluggish, a belt of hot conditions in the last week of August over the north-east sectors of the continent pushed vineyards to get growing even earlier. The spate of warm winds from the west-places such as the Simpson desert provided some of the highest August temperatures on record-36-38 oC, and some inland places recorded over 40oC in the south-east of Queensland.

What is even more disconcerting is that the same regions are looking at a dry spring whereas it is the norm for early rains. That is explained by that fact that El Nino is with us in the western Pacific in all of the Southern hemisphere and that most summer rainfall will fail. To work out were that failure occurs just choose a radar map on a weather site and view all the heavy rains falling into the sea instead of up against land. All that is happening is that salt is being diluted and I am crying when I see this occurrence-fate is an awful experience when droughts persist.

All is not lost-many vineyards have good dam reserves because pre-El Nino, there was a preponderance of winter rains in May-out of season, resulting in lots of heavy rainfall and a saturation of the soils which collect groundwater.

A dry spring is the typical Mediterranean cycle which is in play to the west of Australia’s Great Dividing Range (which separates high rainfall sites at its east from low rainfall sites to the west). The Mediterranean stereotype is operating in Victoria, Tasmania, South Australia and Western Australia, whereby most of the annual rainfall falls between May and August; with the effect of filling the soil profile even to an extent of waterlogging the roots of low-lying vineyards while they are dormant. As the vineyards come out in buds, then shoots and subsequently grapes, the need to use the supplementary water does not really kick in until summer when temperatures, and moisture loss from leaves become significant.

Most of Austalia’s southern most, central and western vineyards are served with this winter rainfall pattern. In wine regions east of the Great Dividing range in Victoria, New South Wales and Queensland, the annual rains fall over summer (usually storms) rather than winter, and consequently give the vineyards great vigour as the summer progresses.

Both the southern Mediterranean climes and the northern temperate climes are liable to receive hot, dry winds circulated by pressure gradients from Australia’s central inland deserts. During 2008 and 2009 the southern regions of Victoria and South Australia, usually tagged “cool region” were dogged by short but continuous periods of hot weather. In 2009 it was twelve days of 43-45 oC heatwaves in February while in 2008 the scorcher struck in March with eight days of super-stress for any vine trying to ripen its berries.

Quite a number of Yarra Valley wineries have already announced that 2009 red wines will not be released. This heatwave came in front of the awful fireballs which caused death, vineyard and bush destruction in the Yarra area, and elsewhere on February 7.

Two regions to have dream vintage conditions in 2009 were Granite Belt (Queensland) and Margaret River (WA).

The vintage 2010 we enter with some awe, trepidation and concern yet with the typical Aussie expectation that some great wines will be made. At this point we are not sure where.