Unprecedented heat in mid-November is ravaging Brazil and other parts of South America amid a record period of hot weather on Earth.
A fan dies at a Taylor Swift concert amid extreme temperatures in Brazil
Although it is still spring in the Southern Hemisphere, temperatures have risen well above normal even in summer, which is just over a month away.
A high-pressure stagnant zone, El Niño, and human-caused climate change have converged to generate this extreme heat.
Rio has experienced a stifling mix of heat and humidity for days. On Friday, when the woman died at a Taylor Swift concert, midday temperatures exceeded 100 degrees and dew points, a measure of humidity, were in the upper 70s. Any dew point above 75 degrees is excessively humid.
At dew point 77, there are about 23 grams of water, or about 1.55 tablespoons, per cubic meter of atmosphere. That’s roughly the weight of nine pennies.
Heat indexes on Friday — a measure of how humid it feels — topped 120 degrees. Climate historian Maximiliano Herrera chirp The heat index reached 137 degrees in the suburbs of Rio on Saturday.
The higher the heat index, the less sweat evaporates from our bodies. This is because the air is already closer to its ability to store moisture. At higher heat indexes, less heat can evaporate from our skin and cool us down as a result. This can lead to difficulties regulating body temperatures. If left unchecked, heat exhaustion and heat stroke can occur.
Temperatures on Saturday around Rio were dangerously high and setting records. Rio’s Jacarepagua-Roberto Marinho Airport reported a heat index of 131 degrees Saturday morning, the product of a temperature near 97 degrees and a dew point of 86. Most of the city’s other airports saw high temperatures between 105 and 107 degrees.
According to Herrera, the temperature in the town of Cerubedica, a suburb located about 25 miles west-northwest of Rio and 15 miles inland, reached 108.7 degrees, a record high for November.
Record temperatures also spread to Peru and Bolivia. On Saturday, maximum temperatures of 102.6 degrees in Tingo de Bonaza, Peru, and 102.2 degrees in Cobija, Bolivia, set records for November. According to Herrera.
The heat first moved to Brazil about a week ago. The BBC reported that red alerts had been issued for about 3,000 towns and cities due to the “unbearable” heat. On November 12, the temperature in Rio reached 108.5 degrees, a record high for the month.
The heat is expected to ease somewhat after Sunday, but temperatures are expected to remain warmer than normal over the next week in central South America.
What drives heat?
Contributing to the heat was a surface high-pressure system rotating counterclockwise off the coast of Brazil. This has brought in warm, humid northerly winds, pumping out the same kind of moisture characteristic of the Amazon rainforest. There is also a “heat dome” or ridge of sinking hot air at higher altitudes. While keeping the jet stream and any inclement weather and cloud cover at bay, it enhances the sun’s hot rays.
The heat is also being enhanced by an intensification of El Niño, the weather pattern associated with warmer-than-normal ocean waters in the tropical Pacific.
Furthermore, the frequency, intensity, and duration of extreme heat events, such as this one, are increasing due to human-caused climate change. The planet just experienced its warmest 12-month period on record and the past five months have been the warmest on record.
According to the United Nations, Brazil’s temperature has risen by 0.9 degrees in just the past few decades. Land use changes, including Amazon deforestation, are expected to accelerate warming.
