By Jake Spring

BRASILIA (Reuters) – The number of fires in Brazil’s Amazon rainforest has receded, falling 36% in September from August to well below a 20-year historic average for the month, amid improved weather conditions and containment efforts by the country’s military.

Fires during the first eight months of the year had surged to their highest since 2010 in August, according to data from Brazil’s space research agency INPE. That news drew a global outcry that Brazil was not doing enough to protect the world’s largest tropical rainforest, a bulwark against climate change.

But in September, the blazes were at the lowest since 2013, dragging down the number of fires year-to-date compared to previous years, according to INPE. From Jan. 1 through Oct. 3, this year is now the worst for fires in Brazil’s Amazon only since 2017.

The fires in the Amazon are largely man-made and not natural, likely set by farmers to clear land for agriculture, according to scientists. In the dry season – roughly from May to September, although it varies year to year – the fires often get out of control as the vegetation is dry and there isn’t enough rain to help curtail the blazes.

The drop in September is likely partly due to President Jair Bolsonaro authorizing the military to fight the fires in efforts that began on Aug. 24, and partly to improved rain conditions, said Maria Silva Dias, a professor at University of Sao Paulo, who has studied the interaction between forest fires and the weather.

“In the more populated areas you might have a greater effect of the army extinguishing fires and putting some sense into people who would just burn the land to clear it with no care whether this fire will spread,” Dias said.

But the Amazon is so vast that the military is unable to fight fires in much of it, she said.

“The weather helped in some sense. Where it rained, it extinguished fires,” the atmospheric science professor said.

The rainy season, which on average starts on Sept. 20 with regular precipitation, is a bit late this year, she said. But more relief appears to be on the way with scattered rain forecast across the region over the next five days.

“We will probably have a more regular chance of rain everywhere, so it looks like it’s picking up,” Dias said.

(Reporting by Jake Spring; Editing by Bernadette Baum)