Mexico's drought is caused by the Hadley cell phenomenon
The drought crisis that Mexico faced in the first months of the year and that reached almost 85 % of the country's territory under that condition has its origin, among other factors, in the meteorological phenomenon of the Hadley cell. To understand this problem, it is necessary to take into account the location of the country, which coincides with the area of the great deserts of the planet.
The northern part of the country is located between 30 or 35 degrees latitude and this coincides with the same latitude of the Sahara and Arabian deserts, which has to do with the phenomenon known as the Hadley Cell. In this phenomenon, the air rises in tropical zones and descends in subtropical zones and Mexico has this zone of descent in its northern part and therefore has desert zones in the states of Sonora, Chihuahua, and Coahuila and the peninsula of Baja California.
In this area, it rains little, but there are also years when it rains even less than average and that is when a drought condition can be declared, a recurrent but not permanent phenomenon that has to do with the amount of rainfall. According to the National Water Commission's Drought Monitor as of May 31, 72.63% of the country has moderate to exceptional drought conditions.
The United Nations designated this June 17 as the 2021 Day to Combat Desertification and Drought which focuses on transforming degraded lands into healthy lands and has as its slogan "Restoration. Lands. Recovery." In Mexico, according to the Sustainable Rural Development Law, the concept of desertification applies "to all the ecosystems existing in the national territory, due to the fact that the loss of the productive capacity of lands is not restricted to dry areas".
Desertification is the loss of the productive capacity of the land, caused by man, in any of the existing ecosystems, in this case, in the Mexican territory. In 2020, the UN reported that 55% of the Mexican territory was affected by water and wind erosion, so it called on the Mexican government to fight desertification, according to a statement issued by the National Autonomous University of Mexico (UNAM).
A decade ago, the United Nations Convention to Combat Desertification, created in 1996, pointed out that among the most important consequences of desertification were the decrease in food production, infertility, and soil salinization. In addition to the reduction of the land's natural recovery capacity, an increase of floods in the lower parts of the basins, water shortage, health problems, and even the loss of societies' means of subsistence, which could contribute to stimulating migration.
The country suffers from this phenomenon because it is a very large country - two million square kilometers in area - but at the same time, there is a very rainy area in the southern and southeastern states, while in the north there are areas with little or no rain as well as very hot weather. Strict water monitoring is necessary because it is important for Mexico to have a record of how much water resources are available, how much water is falling, and even to know the future outlook, at least for the next few weeks or months.