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What does El Niño mean for South
Africa this year and what to expect?
Seminar El Niño
19 November 2015; Johannesburg
By
Mnikeli Ndabambi
General Manager: Operations
South African Weather Service
www.weathersa.co.za
Doc Ref no: SAWS-RES-El-Nino-Seminar.001.01
• El-Niño Southern Oscillation (ENSO) is one of the most important and universally dominant mode of climate variability.
• ENSO may lead to large-scale changes in sea-level pressures, sea-surface temperatures, precipitation and winds across many other regions of the world.
Introduction
Sea-surface temperature (SST) anomalies
of September 1997 (El Niño of 1997/98)
Sea-surface temperature (SST) anomalies of
November 1988 (La Niña of 1988/89)
Doc Ref no: SAWS-RES-El-Nino-Seminar.001.01
• ENSO has long been known to have impacts on the seasonal-to-interannual rainfall variability of South Africa.
• For example, during most of the strongest El Niño events (e.g. 1982/83, 1991/92 and 2006/07) drought conditions occurred, while La Niña events caused excessive seasonal flooding (e.g. 1999/2000 and 2010/11).
Introduction
About 50%-60% of the time most part of
South Africa receives below-normal rainfall
during El Niño (based on historical observed
analysis)
Doc Ref no: SAWS-RES-El-Nino-Seminar.001.01
El Niño 2015 vs 1997?
• These two El Niño episodes are among the strongest in historical record (in the last 50yrs) in their ocean heat content
• Most drought in SA generally associated with El Niño episodes
• However, South Africa never experienced drought in 1997/98 as severe as in 2015/16 (i.e., not all droughts or Floods necessary explained by ENSO)
• Other modes of climate variability may also explain SA climate system such as the Southern Annular mode (SAM), India Ocean Dipole (IOD) which tend to reinforce or counteract the impact of El Niño on South Africa
Courtesy: NOAA
Doc Ref no: SAWS-RES-El-Nino-Seminar.001.01
El-Niño 2015 vs 1997?
• However, in 1997/98 ocean-wide cooling while in 2015/16 ocean-wide warming over the Indian Ocean
• Warming of the ocean enhance convection rainfall over the ocean and subsidence over the sub-continent
Doc Ref no: SAWS-RES-El-Nino-Seminar.001.01
Seasonal outlook 2015/16
Doc Ref no: SAWS-RES-El-Nino-Seminar.001.01
Climate Watch Advisory http://www.weathersa.co.za/media/data/longrange/gfcsa/scw.pdf
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[Drought years (<80% of normal) are indicated in orange]
What to Expect in South
Africa and Southern
Africa…
Doc Ref no: SAWS-RES-El-Nino-Seminar.001.01
Ruacana-Namibia
Victoria falls-Zimbabwe
What to Expect in South Africa…
• Below normal rainfall is predicted.
o Above normal temperatures predicted
• Most Severe drought, which is already being experienced is during this El Nino Episode of 2015
• Possible Socio Economic impacts
Doc Ref no: SAWS-RES-El-Nino-Seminar.001.01
Direct drought induced socio-economic ‘losses’ include the
following:
• Reduced crop, ranch land, and forest productivity,
• Increased fire hazards,
• Reduced dam water levels and therefore water shortages (water rationing/ cuts)
• Increased livestock, wildlife and fishery mortality rates,
• Power challenges in heavy industry sector,
• Increased insect infestations and plant diseases,
• Decline in agricultural yield and agro-dependent industries,
• Increased unemployment in the agricultural sector and all drought- affected industries,
• Strain on financial institutions (capital shortfalls, credit risks, lesser agricultural sector loans and repayment challenges),
• Loss of revenue to the state and local governments (from reduced tax base),
• Increase in basic commodity and food prices
• Lowered living standards especially for subsistence farming communities
Doc Ref no: SAWS-RES-El-Nino-Seminar.001.01
Who is most likely to suffer the most?
Drought effects will be felt by: - Municipalities, Business Community, Agricultural enterprises, - Households and Individuals, - Government (at National, Regional and Local level). - Everyone……(you and me)
In South Africa, worst affected regions are: - KwaZulu-Natal, the Free State, Limpopo, North West and the Northern Cape, where
farmers growing white and yellow maize, soya beans and sunflower have already incurred major losses. We have already observed impacted livestock farming.
A report released by the UN’s food and nutrition working group in September month found this drought – the country’s worst since 1992 – had caused a decline in maize production that had already led to an increase in food prices of 6.4%.
Doc Ref no: SAWS-RES-El-Nino-Seminar.001.01
Concluding Remarks
• El Niño 2015 and 1997 are strikingly similar
• The atmospheric response difference (2015 being most
severe drought) in Southern Africa may be more explained by differences over the Indian Ocean.
• Prediction of the 2015 El Niño impact on our region is so far successful and is noted quite ahead of time (since August 2015).
Doc Ref no: SAWS-RES-El-Nino-Seminar.001.01
Thank you !
Doc Ref no: SAWS-RES-El-Nino-Seminar.001.01
