The long-lasting effects of El Niño are projected to cause an intense fire season in the Amazon, according to the 2016 seasonal fire forecast from scientists at NASA and the University of California.

El Niño conditions in 2015 and early 2016 altered rainfall patterns around the world. In the Amazon, El Niño reduced rainfall during the wet season, leaving the region drier at the start of the 2016 dry season than any year since 2002, according to NASA satellite data.

Wildfire risk for the dry season months of July, August and September this year now exceeds fire risk in 2005 and 2010, drought years when wildfires burned large areas of Amazon rainforest, said Doug Morton, an Earth scientist at NASA’s Goddard Space Flight Center who helped create the fire forecast.

“Severe drought conditions at the start of the dry season set the stage for extreme fire risk in 2016 across the southern Amazon,” Morton said.

Warmer sea surface temperatures in the tropical Pacific (El Niño) and Atlantic oceans shift rainfall away from the Amazon region, increasing the risk of fires during dry season months.

Fires in the Amazon have local, regional, and long-distance impacts. Agricultural fires that escape their intended boundaries can damage neighboring croplands and Amazon forests. Even slow-moving forest fires cause severe forest degradation, as Amazon rainforest trees are not adapted to fire. Together, intentional fires for agricultural management, deforestation, and wildfires generate massive smoke plumes that degrade regional air quality, exacerbating problems with asthma and respiratory illness. Smoke from Amazon fires eventually flows south and east over major urban centers in southern Brazil, including São Paulo and Rio de Janeiro, contributing to air quality concerns.