Fire and deforestation dynamics in Amazonia (1973-2014).

Area of Science:

• Environmental Science
• Atmospheric Science
• Ecology

Background:

• Consistent long-term fire emissions data are crucial for understanding the global carbon cycle and fire regime drivers.
• Limited data exist for fire emissions prior to the satellite era, particularly in regions like the Amazon.

Purpose of the Study:

• To reconstruct historical fire emissions in the Amazon region using pre-satellite era data.
• To assess the primary drivers of fire regimes in the Amazon, distinguishing between human activities and climate.
• To provide a long-term dataset for improving global vegetation and atmospheric models.

Main Methods:

• Utilized weather station visibility observations to estimate fire emissions.
• Correlated visibility data with satellite-based fire emission estimates and carbon monoxide concentrations.
• Reconstructed fire history in the Amazon (including Arc of Deforestation and Bolivia) from 1973 onwards.

Main Results:

• Visibility data explained 61% of variability in satellite-based fire emissions and 42% in carbon monoxide concentrations.
• Fire emissions were low until 1987, increasing rapidly through the 1990s.
• The observed fire patterns strongly correlated with forest loss, indicating deforestation and degradation as primary causes.

Conclusions:

• Visibility data provide a valuable proxy for reconstructing historical fire emissions in data-scarce regions.
• Human activities, primarily deforestation, have been the dominant driver of increased fire emissions in the Amazon since the 1990s.
• The generated visibility-based fire emissions dataset can enhance the accuracy of global carbon cycle and climate models.