It's 3 o'clock in the afternoon.

The reason Sao Paulo is so dark is because the city is drowning in smoke from a massive fire over a thousand miles away, in the middle of the Amazon rainforest.

And it's not the only one.

Nearly 73,000 fires were recorded in the Amazon between January and August of 2019.

That's an 83% increase from last year.

And it's not accidental.

Forest fires like this one are highly unnatural in the wet rainforest.

Humans are behind this burn.

Every year, huge swathes of the Amazon are deliberately and illegally burned to make room for cattle ranching.

This season is called the "queimada".

And it can lead to wildfires like these ones, which burn massively out of control.

The wildfires have been especially widespread this year, which is also Brazilian President Jair Bolsonaro's first year in office.

And that's no coincidence.

Bolsonaro wants to open up the Amazon to mining and ranching, and has vowed to eliminate all protected areas.

He says the environmental laws that protect the Amazon are suffocating his country.

And he thinks global warming is nothing more than "greenhouse fables."

This kind of rhetoric sends a strong message to those who hope to illegally burn the forest for their own gain:

"Go for it. We're not coming after you. We just don't care."

Illegal cattle ranchers seem to have gotten that message.

And these are the results.

All for hamburgers.

It shouldn't take the financial center of Brazil going dark in the middle of the day to get the world to pay attention to this problem.

Because even when soot isn't plunging 12 million people into darkness, the Amazon is still disappearing at the rate of three football fields a minute.

Humans have already destroyed 15% of the Amazon.

Scientists say if we lose another 10%, the entire ecosystem could collapse.

And that would be catastrophic to life on Earth.

The rainforest isn't just home to countless plants, animals, and indigenous people.

It's one of the most important weapons we have in the fight against climate change.

The massive rainforest absorbs up to 2 billion tons of carbon emissions each year.

That's more carbon than Russia emits.

It also safely stores carbon from decades past.

150 to 200 billion tons of carbon.

That's over 140 years' worth of human emissions.

If the Amazon collapses, this carbon will be released.

That would rock the world with unprecedented rapid warming.

And we would lose our biggest ally in the fight against the climate crisis.

Forever.