“August is basically a dry month. No precipitation is anticipated.” With those words, Darío Ovejero discourages any hope of rain for the next few weeks in Tucumán. The graduate in geography and professor of the chair of climatology of the Faculty of Philosophy and Letters of the National University of Tucumán (UNT) adds that from September the period of water will begin.
With respect to the spring and summer that are coming, the specialist anticipates that they will probably also be dry and with warmer temperatures than usual. “The parameters tell us that the La Niña phenomenon is consolidating. That is why agricultural producers throughout the country are in an uproar. For the countryside, this is the worst condition,” he explains. Although we will have to wait until December – which is when the prevalence or not of the climatic phenomenon is confirmed with certainty, he continues – everything suggests that we would once again be under its effects. “In our province it will cause heat and droughts,” Ovejero details.
La Niña produces a large-scale cooling of the surface temperature in the central and eastern parts of the equatorial Pacific Ocean. This impacts the climate of vast regions of the planet. In Argentina, it leads to droughts. In contrast, El Niño brings rain.
The effects of La Niña began to be felt between August and September 2020, according to atmospheric and ocean indicators. In October and November of that time they reached their maximum peak, according to reports from the World Meteorological Organization (WMO). However, until April of this year his tail was felt. Now, it will be necessary to see if the Pacific returns to its neutral conditions or – as Ovejero says – there will be a return of La Niña. For now and like him, meteorological agencies project up to a 70% chance that for the second year in a row we will have a spring and summer season under their conditions.
“La Niña is not the only factor that influences rainfall, but it is the most important,” the specialist retakes. Given this prediction, he says that the alarms have already sounded in the agricultural sector of Tucumán, mainly towards the east of the province, where the soybean, corn and wheat fields are located. “That sector, bordering Santiago del Estero, is the most vulnerable,” he says.
The people of the countryside are not the only ones who are frightened by La Niña. Last season was fateful in the country in terms of the number and voracity of forest fires. Given that, a second forecast of rains that will probably continue below normal is not encouraging. “A decrease in the normal rainfall record is expected and that causes concern”, synthesizes the specialist.
From the South American Climatological Laboratory, Leonidas Minetti (h) points out that the consolidation of La Niña is a real possibility, but still a bit risky. “You have to wait a little longer,” he says. However, he clarifies that we should not be surprised to have two consecutive summers in the southern hemisphere under La Niña conditions and that people in the countryside have taken note of the omens.
In fact, a report from the Buenos Aires Cereal Exchange highlights that the 2021/2022 climate scenario points to a profile similar to that of 2020/2021, but with less severe features than those observed in the previous season. “In Argentina, La Niña is characterized by a water shortage, which varies in terms of severity, duration and timing. In other latitudes it appears differently,” explains Ovejero.
La Niña and climate change
Basically, El Niño and La Niña are major drivers of the climate system. But now, these natural events take place in a context of global warming, which increases temperatures, exacerbates extreme weather, modifies patterns of seasonal rains and droughts, and thus complicates disaster prevention and management.
“But it is not very clear if its effects are being amplified by climate change,” concludes Ovejero. The temporary cooling that La Niña brought, for example, was not enough to prevent 2020 from being one of the three warmest years on record.
Last year, in Tucumán it did not rain from June to October, with August, September and the first half of October being the driest days. In this 2021, in June some light drizzles were registered in some sectors of the province, before or during the days in which there was snowfall. In July, on the other hand, and so far in August it has hardly rained.