A new video from NASA provides a glimpse of global wildfire trends over the past two decades, showing where fires have intensified due to agricultural practices, including in Africa and Southeast Asia, and climate change.
The 30-second clip uses satellite data to map fires burning on a monthly basis from 2000 to 2019. As NASA explains, the colors in the video are based on the number — not size — of fires observed within a 1,000-square-kilometer area per day. Areas of white indicate more fires, as high as 30 per day, while orange indicates as many as 10 fires and red as few as 1 fire per day.
The data shows clear seasonal trends, with lightning-triggered fires in North America and Eurasia during summer months, as well as fires set to clear land for agriculture during the dry season in August, September, and October in South America, Asia, and Africa. It also shows longer-term trends, including the rapid expansion of agriculture into tropical forests in Central Africa and Indonesia over the past two decades, and an increase in the severity of fires in the Northern Hemisphere due to climate change.
But as NASA noted, “Africa is truly the fire continent.” On an average day in August, satellites typically detect 10,000 actively burning fires around the world — 70 percent of which are in Africa.
In the past week, much media and political attention has been given to the sudden spike in wildfires in the Amazon rainforest, particularly in Brazil. But the country actually places third in the number of fires actively burning per country, according to Weather Source, a climate analysis firm. Over a 48-hour period last week, Angola had 6,902 active fires, the Democratic Republic of Congo had 3,395, and Brazil had 2,127. Earlier this year, more than 250,000 fires were burning simultaneously across Africa during a one-week period in June, primarily from slash-and-burn agriculture, according to NASA.
While NASA’s new video does show regional upticks in certain parts of the world, scientists made clear that the total number of square kilometers burned globally each year has dropped roughly 25 percent since 2003. This has largely been due to population growth and development in grasslands and savannas, as well as to an increase in the use of machines to clear farmland.
“There are really two separate trends,” said James Randerson, a scientist at the University of California, Irvine who worked on the new wildfire video. “Even as the global burned area number has declined because of what is happening in savannas, we are seeing a significant increase in the intensity and reach of fires in the western United States because of climate change.”