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Drought of commonsense

''"And it never failed that during the dry years the people
forgot about the rich years, and during the wet years they lost all memory of the dry years. It was always that way."
- John Steinbeck, East of Eden ''


What is a drought? In Bali it is considered 6 days without rain. In many places 7 rainless weeks is the criterion. But there is no agreement beyond borders, it is subjective. No one talks of drought in Western Australia where some places have had no rain for 2 years. They just call themselves dry-land farmers.

Undeniably we have been suffering serious dryness, especially in the past 30 days. Some did have small amounts of rain over the past 4 weeks, like Whitianga, Gisborne, and Kaikoura who had received about 20mm, and Invercagill which had over 30mls. And it is probably a fact that unusual seasonal heat made matters worse by killing grass more quickly.

Up till Friday a public Yahoo poll had asked, are drought conditions hitting you hard? The results were Yes, things are desperate (1325) 23%, Yes, but it's not that bad (1952) 34%, Not at all (2423) 41%, and I don't know (92) 2%. More answered yes than no, but the largest category said they were yet to be affected. With rain having arrived, albeit not enough to eastern districts, are we now still in drought mode?

It was interesting that last week an ex-NIWA Head Scientist burst into the national headlines with his view that this was now the worst drought since the war. This was changed the next day to the worst in 70 years and then revised to the worst in 50 years. While they squabbled over how many decades another group of scientists tipped all the tables over and called it the worst drought in the North Island of NZ in all of its history.

This was then seized upon by every newspaper as evidence that global warming was visible and real and the planet was coming to a quick crispy end. Then I wondered, which history could he have been referring to? The Pakeha history goes back 244 years, and there would not be scientists still alive today who remember Capt Cook, especially as there were no meteorologists then. There have been about 50 droughts since Cook’s time, but no one has quantified them all. Alternatively if you are Maori your idea of history would go right back to Kupe.

Personally I do not believe the climate is changing. We have droughts about every 4-5 years. The last one was in 2007-2008 and that cost the country $3billion, and it kicked off our recession. Prior to that there was a very bad, almost nation-wide one from 2000-2001 that crippled most districts for about 6 months. Before that was the event called the 1997-98 El Nino drought which cost the country half a billion dollars.

Going back another 4-5 years saw the 1992 serious 'power shortage' drought when the southern hydrolakes completely dried up. Electricity prices soared and the country was told it was the shape of dry conditions for the next century because of “runaway” global warming. But the lakes have never been that low since, and we found out later that the energy company had made a dry season worse by letting water out all autumn to keep levels low so that they could run gas and oil generators which charged out power at higher rates.

A few years prior to that was the 1987-88 Canterbury drought which cost our economy $360 million. At the risk of boring the reader with this repetition, before that was the 1982 drought in the Waimea, before that the drought of 1976 and before that the 1972 drought in Marlborough. In the 41 years since 1972 we have suffered 9 or 10 droughts, an average of one every 4-5 years. This one is now itself almost history.

More rain is expected in a week’s time for the North Island, from another tropical low coming down through the Pacific. Easter weekend is expected to be wet for all districts north of Oamaru. A dry week starts April, but the second and third weeks of April are expected to bring rain to the North Island, some torrential. April may be the second wettest month for the year after July.

It is not coincidence that every 4-5 years there's a switch in what the moon does and every 9-11 years in what the sun does. The moon is responsible for the Declination cycle or the ‘Southern Oscillation Index’, which some describe as El Nino and La Nina. The sun has its sequential Sunspot cycle, the peak of which we are approaching this year. Due to these contributions from both sun and moon we get droughts every decade and half decade in NZ.

We could better manage droughts by preparing for the next one about three years after each last one. It means arranging for irrigation systems and dry feed in storage well ahead of time, planned increases and reductions of stock to suit the pattern, and rotation of cropping pastures saving until droughts paddocks better suited to drier conditions because they are closer to waterways. In this way we can fit farm practice to the known drought sequence rather than having farming families trying to fight it.

But first perhaps the culture of the refusal within the earth-scientific community to consider cycles, because of their conviction that weather/climate is now anomalous (for which there is more funding) also needs to change. We have 2-3 years to think about these matters, before we engage with the next drought about 2017.

Ken Ring of www.predictweather.com is the author of the Weather Almanac for NZ for 2013, published by Random House.