El Nino stalks Southern Africa

30 Aug, 2015 - 00:08 0 Views

The Sunday Mail

Weather forecasts by a number of international weather forecasting organisations indicates that El Nino, whose effects are devastating and far-reaching, is once again heating up in the Pacific Ocean.

El Nino has far reaching consequences spanning from health, disaster risk management, water resources, hydropower management and food security.

According to the latest forecast released by the Climate Prediction Centre, this year’s El Nino is “significant and strengthening”.

In a statement that was widely quoted in the international media, chances of El Nino effects affecting the Southern African region and the Northern Hemisphere are high.

“There is a greater than 90 percent chances that El Nino will continue through the Northern Hemisphere winter in 2015 -2016 and around an 85 percent chance it will last into early spring 2016,” read part of the statement.

The Consultative Group on International Agricultural Research (CGIAR) predicted that chances of El Nino conditions manifesting themselves by the end of the year are as high as 80 percent.

El Ninos occur every two to seven years with varying intensity.

During El Nino years, the start of the farming season can be delayed.

The worst El Nino-induced drought occurred in 1982 and is estimated to have caused between $8 and $15 billion damage world-wide. Southern Africa witnessed its worst El Nino-induced drought in 1991 and the region’s national economies were severely affected. However, the most severe El Nino on record, which occured between 1997- 1998, had negligible effects on Zimbabwe.

In 1997-98, the El Nino led to drought and massive forest fires in Indonesia. Flooding caused massive destruction of infrastructure and crops along the coast of Latin America with livestock and agriculture losses due to heavy rains affecting East Africa.

Epidemics of infectious diseases such as Rift Valley fever and malaria are also common during El Ninos.

Farmers need information on weather patterns so that they can adapt to the impending changes. Once the farmers know that the season may be dry, they can implement water-saving measures such as planting early-maturing and drought resistant crops and culling or reducing herds.

.On the other hand, if the conditions are favourable, the farmers can invest in higher-yielding grades or can plant a larger area.

The Director of the Meteorological Services department, Dr Amos Makarau, said rainfall patterns have become more unpredictable due to climate changes. Speaking during a presentation at the third agro-business annual conference at the Harare Agricultural Show, Dr Makarau said extreme weather patterns are becoming more severe with rains becoming more erratic.

Dr Makarau advised both Government and farmers to invest in irrigation schemes.

“Rains are now violent and strong, destructive winds a common phenomenon. We should be planning for drought each year,” Dr Makarau said.

Professor Amon Murwira, a lecturer in the University of Zimbabwe’s department of Geography and Environmental Science, advised farmers to counter El Nino conditions by harnessing water.

“In a semi-arid country like ours, our farmers should treat each year as a potential drought year. My advice to farmers is very simple – catch the water, store it in reservoirs and then use it reliably,” said Professor Murwira.

 

Understanding El Nino

El Nino refers to warmer-than-normal sea surface temperatures in the eastern tropical Pacific Ocean. The term was coined by fishermen of the coast of Peru, who noticed a periodic warming that affected their catch.

“El Nino” (Spanish for little boy) refers to the Christ child, as the phenomenon tended to occur around Christmas.

La Nina, the opposite of El Nino, signifies periods when the eastern equatorial Pacific is cooler than usual. In general, every three to seven years, either El Nino, La Nina or neutral conditions occur.

El Nino occurs when the equatorial easterly winds over the Pacific are lighter than average in the central and eastern Pacific Ocean.

La Nina on the other hand occurs when the equatorial easterly winds over the Pacific are stronger than average sea surface temperatures (SSTs), resulting in cooler surface water in the central Pacific Ocean.

Neutral conditions occur when winds are near average strength and when sea surface temperatures across both the eastern and central Pacific Ocean are also close to average.

These changes in the Pacific are related to major weather and climate fluctuations around the world, with varying consequences for populations in different locations.

On a positive note however, not all El Ninos result in drought, above normal rainfall and good harvests can be obtained during some.

Scientists are noting changes in the El Nino factor. El Nino used to occur in varying degrees of severity after every five years, however since the 1990s, El Nino effects have appeared in a row, a fact which has been attributed to global warming.

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