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Drier than normal dry season in Brazil

Isaac Hankes
Isaac Hankes
Weather Research Analyst

A drier than normal dry season in Brazil is likely to exacerbate the Amazon fires.

The Amazon spans eight countries, roughly 40 percent of South America, and produces 20 percent of the Earth’s oxygen. In Brazil – home to more than half the Amazon rainforest – over 87,000 forest fires have been recorded in the first eight months of the year, compared with 49,000 in the same period in 2018.

2019 is not the worst year in recent history, however. Brazil experienced more fire activity in 2005, with more than 142,000 fires in the first eight months of that year.

The northern region of Brazil has been most significantly affected by 2019’s fires: Acre, Amazonas, Rondônia, and Roraima have all seen large percentage increases in the number of fires compared with the average of the last four years (2015-2018):

  • Acre 138%
  • Amazonas 81%
  • Rondônia 115%
  • Roraima 141%

Forest fires are common in the Amazon during the dry season, which runs from June to November depending on the region. While fires can be caused by naturally-occurring events, most of 2019’s fires are believed to have been started by farmers clearing land for agriculture or livestock and by loggers. Dry weather, winds and extreme heat exacerbate both fire frequency and intensity.

No Rain in the Rainforest

Our Refinitiv Weather research and analyses indicate a significant dryness risk in the forecast over portions of Mato Grosso, Goias, and Tocantins. A strong consensus among forecast indicators verifies that the areas of potentially significant dryness should be monitored for drought development in the coming months, a time period during which rainfall normally picks up considerably.

Precipitation more than 75 mm below normal is indicated by “–“, precipitation 25-75 mm below normal of normal is indicated by a “-“, precipitation within 25 mm of normal is marked by “=”, and precipitation 25-75 mm above normal is indicated by a “+”. All dry areas are enclosed by brown contours, while wet areas are enclosed by green contours.

Indeed, the forecasted dry weather ahead follows on five years (2014 – 2018) of below normal actual rainfall in the Northern region of the country.

If the forecast holds, drought could develop or worsen in Brazil during September-November, but how long might it last? Trends could develop in the forecast based on such factors as the El Niño Southern Oscillation (ENSO) among others. In fact, some early indications for December 2019-February 2020 suggest that better rains could be ahead by the new year. To learn more about Refinitiv Weather data and outlooks, visit the Agriculture Weather Dashboard and Weather Applications in Eikon.