Monday, August 9, 2010

Global warming and early harvests

The Australian economy has a two-speed drive, and when it comes to global warming-attributed early harvests, once again Western Australia is largely out of step, as is Tasmania and, most certainly, New Zealand. As I have consistently said, it’s difficult to unbundle the effects of drought and moderate warming. (Remember that there has in fact been little or no warming over the past 10 years or more.)

The early harvests of recent years are substantially due to the whole vegetative cycle for the vine starting early and finishing early. In other words, hang time (the period between budburst and harvest) has not been dramatically shortened; it is simply that dry, warm soils have caused trees, shrubs, plants and grapevines to spring into life earlier than normal. Unless the weather in southern Victoria and much of southern South Australia changes radically over the next two months (and the long-range forecasts suggest that there is a better-than-even chance that rainfall will either be normal or above-normal) the vines will enter spring with the soil profile filled with water. This should mean normal budburst and, hopefully, a reversion to a more normal ripening period.

1 comment:

Erl Happ said...

Agreed, there has been no warming over the last ten years. Here is a viewpoint from a student of change in the atmosphere as to why we are currently in what might prove to be a very testing, cooling cycle:

In Margaret River I am is seeing cooler winters and the odd late spring. In 2006 and again in 2010, ripening the late varieties was not easy.

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