Natasha Maguder was in the Amazon region of Brazil for Earth's Frontiers. Watch the show on Wednesday, Nov 24, 08.30, 18.30 Saturday, Nov 27, 8.30, 14.00, 20.30 Sunday, Nov 28, 06.30, 18.30 Monday, Nov 29, 04.30 (All GMT)
(CNN) -- Only when flying over the treetops of the Brazilian Amazon was I finally able to comprehend the scale of the forest.
The Amazon rainforest is the biggest in the world. It stretches into nine different countries, and covers over three million square miles.
These trees are important to all of us. They are vital to the world's water system and the generation of oxygen. One fifth of the world's rainfall comes from the Amazon ecosystem.
As we flew over the forests the views from the aeroplane windows began to change. The lush green carpet of trees gave way to cleared areas with what looked like matchsticks, strewn on the ground.
This is the reality of deforestation. I realized that in all the articles I've ever read about deforestation, I've never been able to picture the reality of what it looks like on the ground. And the scale of the damage is unimaginable.
Paulo Adario, Greenpeace's Amazon Director, says 17 percent of the forest has disappeared. According to the World Bank, the tipping point is 20 percent; when a fifth of the trees have disappeared, the ecosystem will become too unbalanced to function as it should.
The consequence of such change to one of the most important environments in the world is "scary", says the World Bank.
It was a shock to touch down on a small airfield near Boca do Acre in South Amazonas. There the trees were replaced by blackened stumps, and cattle grazed on what was once part of the magnificent green vegetation I had witnessed from above.
Brazil has worked hard to manage the forest. New data is expected to confirm that this last year has seen a drop of almost 50 percent in the rate at which deforestation is happening.
In fact, Brazil is the best country in the world when it comes to fighting the problem of deforestation.
Senator-elect Eduardo Braga represents Amazonas state. He says the people in his state don't deforest because they're stupid, or even because they're smart. He says they do it to survive.
Braga attributes the positive data to better relationships with the forest people, as well as improved satellite technology. Regular scans of the forest show changes to groundcover, and highlight where new damage is happening. This allows the authorities to clamp down on illegal activity sooner.
Paulo Adario has other ideas about the recent slow down.
Food is big business and it is the recent dip in the profitability of food production has slowed the rate of deforestation, says Adario, not only the improved environment policing.
Adario showed me the charred trunk of a Brazil nut tree, an icon of the Amazon. Growing at its base was a corn stalk. A tree like this takes 400 years to grow, he says. And it's being forcibly removed, for the sake of corn, which takes just four months to grow.
Brazil is one of the key countries in favor of the UN's Reducing Emissions from Deforestation and Forest Degradation scheme (REDD), which pays people to look after the rainforest, and teaches the economic importance, says Eduardo Braga.
The COP16 UN Climate Change Conference takes place in Mexico next month, but the wranglings of global governments felt a long way away from Boca do Acre.
Brazilian NGOs and the government are united in their desire to protect the trees. They are pushing for zero deforestation; the rate at which trees are disappearing to slow to a complete stop.
Whether that is attainable remains to be seen.