How big is the Amazon rainforest and what does it matter?

The world's largest rainforest, the Amazon spans eight countries and covers 40% of South America -- an area that is nearly the size of two-thirds of the US, according to the World Wildlife Fund. More than 30 million people live in the Amazon, which is also home to large numbers of mammals, birds, amphibians and reptiles, most of them unique to the region. A new plant or animal species is discovered there every two days.
The Amazon forest, which produces about 20% of earth's oxygen, is often referred to as "the planet's lungs."
An inferno in the Amazon, two-thirds of which is in Brazil, threatens the rainforest ecosystem and also affects the entire globe. 

What is happening and when did it begin?

Since the beginning of 2019, Brazil's National Institute for Space Research (known as "INPE") has reported 72,843 fires in the country, with more than half of these being seen in the Amazon region. This means more than one-and-a-half soccer fields of Amazon rainforest are being destroyed every minute of every day, INPE has stated.
An 80% increase in deforestation has occurred so far this year compared to last year, according to the institute.
Evidence of the fires also comes by way of a map created by the European Union's satellite program, Copernicus, that shows smoke from the fires spreading all along Brazil to the east Atlantic coast. Smoke has covered nearly half of the country and has begun to spill into neighboring Peru, Bolivia and Paraguay.
Even Sao Paulo, more than 1,700 miles away, has inhaled some of the burning forest's smoke. Images from the city show the sky pitch-black in the middle of the afternoon, the sun partially obscured by ash and dark.
Across the globe, people are sharing images and videos that show lines of fire leaving blackened waste.