Farmers and cattle ranchers have long used fire to clear land and make it ready for use, so they are likely behind the unusually large number fires burning in the Amazon today, said Christian Poirier, the program director of non-profit organization Amazon Watch.
This year's fires fit with an established seasonal agricultural pattern, said CNN meteorologist Haley Brink. "It's the best time to burn because the vegetation is dry. (Farmers) wait for the dry season and they start burning and clearing the areas so that their cattle can graze. And that's what we're suspecting is going on down there."
Deforestation is neither new nor limited to one nation.
Across the globe, cleared land is needed to expand agriculture and other activities, such as the cattle ranching, soy production and logging favored in Brazil, according to Nigel Sizer, a tropical forest ecologist and chief program officer with the Rainforest Alliance.
"It is responsible for 80% to 90% of the loss of tropical forests around the world," Sizer said.
Already, 20% of the wider Amazon biome, including not only the rainforest but adjacent regions, has been lost to mining, logging, farming, hydropower dams and roads, according to the World Wildlife Fund.
In the Amazon, this activity can be slowed or done in a much more sustainable way, environmental groups say.
"There has been a lot of analysis and satellite data that shows there is so much land already cleared -- a lot abandoned or very poorly used and managed -- that we could use to grow food on," Sizer said. "We don't need to be clearing new forests to do this in Brazil."
What can you do?
No need to wait around for politicians to act.
To help reforest parts of the world, you can contribute to the Rainforest Trust and Rainforest Alliance. The Arbor Day Foundation also has a program to help save tropical rain forests which provide habitat for some 50% of the world's plants and animals.
You also can buy products that feature the "Rainforest Alliance Certified™" seal. Thousands of products from farms that met standards for sustainability have earned the seal -- including coffee, chocolate and bananas.
If climate change is your worry, there's plenty you can do about that.
Drive less, walk more. If you can afford it, "buy a more fuel efficient car," Sizer recommends. Adjusting your thermostats by just a couple of degrees also makes a difference (while saving you money), he said.
