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Farmers in most of the inland provinces need to prepare for the possibility of drought and increased temperatures this summer, as the global climate event known as El Niño comes to the fore.
The El Niño-Southern Oscillation (ENSO) is one of the most important climate events on earth. It is characterised by cyclical changes in sea surface temperatures and atmospheric pressure patterns and has two primary states: El Niño and La Niña.
During El Niño warmer-than-average sea surface temperatures in the central and eastern tropical Pacific Ocean can lead to a disruption in global weather patterns. This can result in increased rainfall and flooding in some regions, while others, such as South Africa, experience droughts such as the one in the Western Cape from 2015 to 2017. El Niño typically lasts for a period of nine to twelve months but can sometimes last for years.
On the other hand, La Niña is marked by cooler-than-average sea surface temperatures in the same region, which can have opposite effects, including, for countries like South Africa, above-average rainfall and a higher likelihood of flood events.
Both El Niño and La Niña occur in two-to-seven-year cycles, with an in-between transitional period of ‘neutrality’ where ocean temperatures, rain patterns in the tropics, and the winds in the equatorial Pacific Ocean stick to the long-term averages.
The National Oceanic and Atmospheric Administration, a United States government institution, states that the ENSO climate pattern “is humming along in the tropical Pacific Ocean as of early October 2023” and that it’s “virtually certain El Niño will last through Northern Hemisphere winter”.
Apart from generalised warnings from the South African Weather Service (SAWS) of potentially hotter and drier weather, it is difficult for meteorologists to provide exact indications of what the full impact of this El Niño cycle will be on South Africa.
The reason for this is, simply put, the fact that the phenomenon is dependent on unpredictable interactions in the Earth’s climate system. For example, a slight shift in ocean temperature, pressure or winds could impact the scale and intensity of an El Niño event.
Despite the uncertainty, SAWS has provided an overview based on a model forecast, offering insights into what may be anticipated from September 2023 to January 2024. SAWS expects higher-than-average rainfall in most parts of the country from September through to December, but below-average rainfall in parts of the North West, Free State, Eastern Cape, and Northern Cape from November through to January. Additionally, temperatures are expected to be mostly above normal nationwide from September through to January.
South Africa’s farmers have been cautioned by climate experts and government to prepare for hot and dry conditions over the coming summer, and the possibility of severe drought.
Given that the majority of South Africa’s crops are rainfed and do not rely on irrigation, drought poses a major risk to farmers. The Agricultural Business Chamber states that approximately 20% of maize, 15% of soybeans, 34% of sugarcane, and less than half of our wheat production rely on irrigation, while the rest rely on rainfall. This means that, in the event of a drought, a significant portion of the country’s farmers would face challenges.
The Agricultural Business Chamber has warned that if this El Niño event is intense it could lead to the same tough farming conditions as experienced in the 2015/2016 El Niño-exacerbated drought. During this period the harvest of important crops such as maize was reduced by half, from an average 16.8-million tons to 8.2 million tons. As South Africa’s average maize consumption is 11.8 million, the drought made us a net importer of maize, rather than a net exporter. This resulted in increased food insecurity and economic stress.
On the other hand, it is possible that this year’s El Niño event could be mild in nature, like that experienced in 2018/2019 when crops were not too badly affected. During that year maize yields remained consistent with the country’s average consumption.
But in addition to an El Niño event, farmers will more than likely have to continue to contend with load-shedding. Last year load-shedding caused a R32-million loss to the agricultural sector between January and September 2022.
In 2021 the Intergovernmental Panel on Climate Change (IPCC) released its Working Group 1 report. This comprehensive report discussed historical changes, current observations, and future warming projections, as well as delved into the potential impact of climate change on ENSO cycles.
The IPCC is virtually certain that ENSO will continue to exist in a warming world and will continue to play a pivotal role in influencing the world’s climate patterns. Rainfall patterns tied to ENSO are expected to become more variable in the latter half of the 21st century under the majority of warming scenarios. Aside from this, climate models show little consensus regarding exactly how climate change might affect ENSO cycles going forward. This can be attributed, in part, to the sheer complexity of the ENSO system.
This isn’t to say that all climate models predict ENSO won’t change in the next century. Some models do predict change, but there’s no clear agreement. Some models show stronger ENSO events, while others predict weaker ones. The fact that there are so many different possibilities is why the IPCC is not very confident about how ENSO might change in a warming world.
This story first appeared in @GroundUp and is republished with permission.
