The Amazon is nearly the size of the contiguous United States. Two-thirds of it lies in Brazil. 

Deforestation is second only to the burning of fossil fuels as a source of global greenhouse gas emissions, which scientists link to climate change. Researchers say halting and reversing land clearance in tropical forests could reduce global carbon emissions by nearly a third.

Brazil, home to more tropical forest than any other country, reduced forest clearance by 80 percent between 2005 and 2012, dramatically lowering its emissions. Better monitoring of the forest, improved law enforcement, more efficient farming practices, and private-sector initiatives to halt the sale of goods cultivated on illegally deforested land helped bring down the rate of deforestation.

But Brazil has reported an increase in its rate of deforestation since 2012. Individuals and companies continue to profit from clearing land and exploiting natural resources, and authorities are limited in their abilities to track and punish those who do so illegally.