We are in the middle of a strong El Nino which is currently more apparent in the Northern hemisphere, but will shortly becoming apparent here in New Zealand and it would be foolhardy not to take precautions.
The classic outcome from an El Nino event is a colder period in the spring and drought in the summer so I contacted Brett Mullan, Chief scientist with NIWA to ask him for some advice. He very kindly sent me his PowerPoint presentation from a talk that he and Gregor Macara of NIWA gave to Farmers on the South island to warn them of the impending problems and this is a very shortened version of their presentation.
The results of the last three El Ninos show different levels of drought in various parts of the country but the overall prediction from this very strong El Nino is that we will have a severe drought. As the graphic shows we are already very short of rain and the moisture content of the soil is already low we are in a very vulnerable position.
The graphic shows how the country fared in the 1972/3 El Nino drought and the current event is of similar strength or even stronger.
Climate change has changed the pattern of wind over New Zealand over the last fifty years so that we are getting a higher proportion of westerly winds and, as it is the Easterly’s that bring us the rain, we are already getting a higher incidence of drought.
Despite the forecast for drought the other problem with an El Nino is that the warmer water will make a cyclone more likely and the Northern Pacific has had a very busy cyclone season and we will most probably suffer the same fate. Cyclones are very unpredictable so whether we get hit is in the lap of the gods but just because a drought is forecast it does not reduce the likelihood of a cyclone and they are extremely damaging due to flooding and soil erosion.
Farmers and gardeners in particular need to be aware that we may have severe drought after Christmas and take necessary precautions to preserve plants and stock.
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