KANSAS CITY, MISSOURI, US — Weather conditions in Brazil so far this spring have been poor in many areas and if a turnaround does not occur soon production may be notably off the trend as it was in 2015-16 and 2020-21. In 2015, El Niño was solely responsible for lower grain and oilseed production. This year is a bit different.

World Weather, Inc. forecasters believe that El Niño has certainly had much influence on this year’s adverse weather as it did in 2015-16, but so has the 22-year solar cycle and the lingering atmospheric effects of the Jan. 15, 2022, Hunga Tonga volcanic eruption. Dryness in 2020-21 was much different and mostly the byproduct of La Niña.

El Niño events have a big influence on weather throughout the world. Typically, in South America the influence starts off with a delay in the onset of monsoonal moisture in the Amazon River Basin. This year’s drier-than-usual bias kicked in after a prolonged period of drought already had depleted water supply and soil moisture throughout the Amazon River Basin. Water levels were already at a critical low long before the rainy season was supposed to begin and when El Niño came along it prolonged the dryness long enough to set records for low water levels on the Amazon River and many reservoir and lake levels associated with the seasonal rainfall.

Historical weather and atmospheric data have suggested that this particular 22-year solar cycle always had a bad reputation for making weather more extreme. The phenomenon impacts all areas on the planet and in most cases it makes weather anomalies more serious, resulting in greater impacts on agriculture and human life. The association between the 22-year solar cycle and socio-economic trends has been written about multiple times over the past couple of centuries.

From a weather perspective, no region has documented the solar cycle better than the United States, where famous drought and extreme weather years like those of the 1930s, 1950s, 1999-2002, 1911-13, the 1970s and the late 1880s can all be tracked back to this cycle. Data from South America has not been studied nearly as much as that of the Northern Hemisphere, but the trend is likely in place there as well and may have contributed greatly to the unusually dry and hot weather of 2023.

Already in the past few weeks the Vegetative Health Index (a satellite interpreted vegetative greenness comparison tool) has shown conditions in Brazil to be worse than those of 2015 in some areas and better in others. The Vegetative Health Index (VHI) determines where crops are unhealthy, under-developed or not planted relative to normal based on previous satellite imagery. The VHI has shown that conditions in northeastern Brazil and the Amazon River Basin may not be as bad as that of 2015, which is interesting because most of the water supply in the basin is at record lows.

Drought-induced stress seen in the VHI over southern Mato Grosso and much of Mato Grosso do Sul can be clearly seen in satellite imagery. Crops in these areas are confirmed to be suffering from too much heat and dryness and the situation is much worse than that of 2015. Recent images from outer space also have suggested that summer crops from southern Minas Gerais through Sáo Paulo to southern Mato Grosso do Sul and northern Parana have been the best in the nation this year, but conditions were even better in those areas during 2015.

Farther to the south, too much rain and flooding frequently has damaged spring and summer crops from Rio Grande do Sul into southern Parana. This, too, is seen in the lower (more stressed) VHI data compared to that of 2015. Overall, the VHI seems to be suggesting worse agriculture conditions in interior southern Brazil this year relative to 2015 while the situation in northern and eastern Mato Grosso, Goias and immediate neighboring areas are also worse than those in 2015.

The assessment also has suggested crops farther north in Mato Grosso, Tocantins and Maranhao, Piaui, Bahia and northern Minas Gerais may be better than those of 2015. However, there has been an acceleration in the VHI stress levels in recent weeks. If this trend of adverse weather is not soon stopped the decline in 2023 crop production in Brazil is destined to be worse than that of 2015, which was the most recent year of significant production cuts for soybean and corn.

One more important factor to this year’s adversity in Brazil may be associated with the lingering effects of the January 2022 Hunga Tonga volcanic eruption that brought a 10% increase in moisture to the stratosphere. Scientists have measured and confirmed the increased moisture in the stratosphere and they also speculated shortly after the volcano erupted that the world’s weather would be influenced by the event for upwards to five years.

In addition to that, the prediction included a statement suggesting one of those five years would include a notable deviation in normal atmospheric warming trends just like that noted around the world in 2023. There is growing evidence that the unusual warmth occurring throughout the world this year is associated with the Hunga Tonga volcano.

Proving the influence from the volcano will be difficult since the eruption in 2022 was unprecedented in modern history. The underwater volcano was stronger than Krakatoa in 1883 and particulate matter and moisture associated with the eruption reached upwards 36 miles into the atmosphere.

Brazil’s heatwave this spring and that noted in Argentina, South Africa and Australia is similar to that which occurred in North America, Europe and parts of Asia in the Northern Hemisphere summer of 2023. World Weather, Inc. believes that Brazil’s unusual rainy season and recent heatwave can be largely attributed to El Niño, the 22-year solar cycle and the lingering effects of the Hunga Tonga volcano. Monsoon moisture in both North and South America this year was below average, and the evidence also is pointing to the volcanic eruption, although that has not been proven yet.

Scientists believe it will take a few more years for the influence of the Hunga Tonga volcanic eruption to wash out of the atmosphere. Each of the next few years should progressively move back to a more “normal” trend in atmospheric indices. In the meantime, there is a relatively good potential that Brazil’s weather will not return to normal this spring or summer and a further decline in production and vegetative health should be expected in at least a part of the nation.  

Drew Lerner is senior agricultural meteorologist with World Weather, Inc. He may be reached at worldweather@bizkc.rr.com. World Weather, Inc. forecasts and comments pertaining to present, past and future weather conditions included in this report constitute the corporation’s judgment as of the date of this report and are subject to change without notice.