Welcome to the inquiry on the BBC World Service.

I'm Duncan Weldon.

Each week, one question, four expert witnesses and an answer.

It's 5 to 4 in the afternoon of August the 20th this year and the sky over Sao Paulo has just turned dark.

It should be light for another two hours, but sunset has come early today in Brazil's bigger city. Street lights have been switched

on and traffic has slowed to a crawl. The cause of this premature night is the smoke

from fires burning thousands of

kilometers away in the Amazon rainforest. The pictures of the flames, the smoke,

and the burned-out remains spread around the world.

Pray for the Amazon trends across social media.

France as President Macron tweets that,

our house is burning.

With the world's attention firmly caught, the Amazon fires find themselves on the agenda for the meeting of G7 leaders.

But the Amazon is one story among many.

The global community has long worried about deforestation.

Five years ago, nations agreed to halve global tree loss by 2020 and end it by 2030. This month it was announced those targets will be

missed. So this week we're asking how can we save our forests?

Part 1, Empty pixels.

It looked completely like a desert, just like keeps of sand and no vegetation in sight. It's like the surface of the moon.

It was that devoid of life.

Our first expert witness, Michaela Vice, travelled to Peru during her master's degree to study forest conservation.

But the thing she vividly remembers is an illegal gold mining operation.

...