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Southern Hemisphere Harvest: Navigating Weather Patterns

Scott Patterson • March 27th, 2024.

El Nino vs La Nina Impact on Australian Crops

The Southern Hemisphere Harvest versus El Niño

The 2023-2024 harvest has begun and, for many regions in the southern hemisphere, the yields will be low to non-existent. This is because heat and drought have affected large swaths of Brazil, southern Africa, and Australia. While La Niña is anticipated to bring better growing conditions, the La Niña will likely not have a significant influence until next summer.

Weather Recap

The growing season in the southern hemisphere in 2023-2024 experienced a combination of a strong El Niño, a strongly positive IOD (Indian Ocean Dipole) and periodic strong phases of a more frequently occurring MJO (Madden-Julian Oscillation). Each pattern behaves differently over the course of the growing season, affecting crop production. El Niño tends to stretch across the entire growing season and cause more known issues like heat and drought in Brazil and northern South America, drought across southern Africa, and drier conditions in Australia and Indonesia. The IOD occurs in the spring and leads to widespread, extremely dry conditions. The MJO comes and goes every other month. This leads to sudden periods of heat and drought or heavy rain and flooding and is much less predictable.

The impact of these patterns meant too little rain for too long and at the wrong time in the growing cycle for many types of crops, from cocoa beans near the equator, to corn and soybeans in Brazil, and corn in southern Africa. Long periods of scorching hot temperatures resulted in heat stress for many crops, adding to the challenges of the growing season.

Weather Effects on Crops in Specific Regions

South America

El Niño and La Niña form in the Pacific Ocean, along the equator and just off the coast of South America. These weather patterns are usually fairly predictable in terms of precipitation and temperature anomalies during El Niño or La Niña and over seasonal timelines. Patterns such as the IOD and MJO create less predictable patterns sub-seasonally and can be the real reason why one area is so much drier than another. This occurred between Mato Grosso and Rio Grande in Brazil.

El Nino vs La Nina - Impact on Brazilian Crops

Map image showing specific crop growing regions and the impact
El Niño or La Niña had or is expected to have on that region.

Africa

Similarly to South America, Africa experiences specific weather patterns with El Niño and La Niña. El Niño led to very dry conditions and low crop yields, along with low water levels in general for southern African countries. The IOD and the MJO both can affect this region and bring seasonal to sub-seasonal weather patterns that amplify the influence of El Niño or La Niña. This is what occurred this growing season in southern Africa and will result in low yields for many crops sensitive to heat stress and drought.

El Nino vs La Nina Impact on African Crops

Map image showing the effects of El Niño and La Niña on crops that grow
in southern Africa.

Australia & New Zealand

Similarly to other regions, Australia and New Zealand are both influenced by El Niño and La Niña weather patterns. El Niño often leads to a dry, hotter summer in most of Australia, but this depends heavily on where the center of the El Niño is based. This growing season, we also saw a strong positive IOD in the Indian Ocean that caused extreme heat and drought during the spring. The IOD tends to have peak influence through November and then weaken, which is what happened this growing season. Rainfall increased significantly in December for Queensland and New South Wales. Furthermore, the MJO formed and was at the strongest phase just north of Australia in Indonesia, leading to a big uptick in rainfall and tropical cyclones.

While it has finally dried out for eastern areas, La Niña will bring an increased risk for more heavy rainfall, flooding, and cool temperatures to eastern areas. Conditions will be closer to normal for the western regions.

New Zealand may seem close enough to Australia to experience the same weather, but it has very different conditions that make its weather unique, due to its location. Not only is the weather vastly different than Australia, but weather can vary widely from eastern to western New Zealand. This is because there are warmer waters in the Tasman Sea between New Zealand and Australia and warm water temperatures across the wide open Pacific Ocean to the east, with colder water near Antarctica to the south. Generally La Niña favors a drier spring in the east, then a wetter summer into fall.

Vineyards in New Zealand are found along the east side of the south and north islands. Wine production could be affected, due to too much rain and cloud cover, along with cooler temperatures. Wine grapes need sunlight and warmer temperatures throughout the day to properly develop sugars to balance the grape’s acidity.

El Nino vs La Nina Impact on Australian Crops

Map image showing locations of grapes and apples in Australia and New Zealand. 

Conclusion

A trio of global weather patterns, the El Niño, the IOD, and the MJO caused unexpected conditions for the growing season in 2023-2024. This resulted in significantly reduced crop yields for some areas, but an unexpected surplus for other regions. With the transition from El Niño to a La Niña by the start of spring, many of the largest growing regions in the southern hemisphere will see a shift to wetter conditions. This should lead to higher yield production for corn, legumes, grains and cocoa. For more information for specific crops and how climate intelligence insights can help you make better decisions in-season and long term, reach out to us at ClimateAi.

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