Brazil has recently experienced a severe heatwave that has broken records and caused widespread discomfort and even health problems for many residents. The heatwave began in mid-November and has persisted for several weeks, with temperatures in some parts of the country reaching as high as 46 degrees Celsius (115 degrees Fahrenheit). This is well above the average temperature for this time of year (summer starts just in December in the South Hemisphere), and the prolonged heat has been particularly hard on vulnerable populations such as the elderly and the poor.
The heatwave has been attributed to a number of factors, including climate change, El Niño, and deforestation. Climate change is causing global temperatures to rise, which is making heatwaves more frequent and intense. El Niño is a natural climate pattern that occurs every few years and can cause changes in weather patterns around the world, including increased temperatures in Brazil. Deforestation is also contributing to the heatwave, as trees help to regulate the climate and their removal can lead to hotter temperatures.
EL Nino
Researches in Brazil believe that the heat wave is strongly associated with the El Niño phenomenon. It is characterized by the weakening of the trade winds (which blow from east to west) and the abnormal warming of the surface waters of the eastern portion of the equatorial Pacific Ocean. Changes in the interaction between the ocean surface and the lower atmosphere have consequences for weather and climate in different areas of the planet. This occurs because the circulation dynamics of air masses take on new patterns of moisture transport, affecting temperature and the distribution of rainfall.
Geographer Marcos Freitas, a researcher at the Federal University of Rio de Janeiro (UFRJ), draws attention to measurements carried out by the National Oceanic and Atmospheric Administration, linked to the US government. The agency, he pointed out, gauges the temperature of the water in the so-called Zone 3.4, located in the central equatorial portion of the Pacific Ocean.
“We’re getting close to a 2ºC anomaly. Usually, we have a medium or weak El Niño every two years, which is when we see an anomaly of 1ºC at the most. When it rises above 1ºC, we call it a strong El Niño. This alters the air masses over our continent.”
“We’re facing a strong El Niño,” he argued, which is blocking the entry of masses of humidity in part of the Southeast and a little in the Center-West.
The trend also points to a sweltering summer, he went on to say. “This El Niño is not going to dissipate now,” he added.
The World Meteorological Organization estimates that the effects of the phenomenon should be felt until at least April next year. Marcos Freitas noted that a strong El Niño occurs more or less every seven years, but its intensity has been on the rise as a result of global warming.
Source: Agência Brasil