[onscreen text] Tracking Amazon Deforestation
[Doug Morton] The Amazon is the largest tropical rainforest in the world. At over six million square kilometers the Amazon basin, and the tropical forests that it holds, are about the same size as the entire continental United States. Home to millions of people and tens of thousands of species.
Landsat is NASA's longest-running record of our changing planet. Data have been taken from Landsat satellites since 1972, and that allows us to go back in time over several very important decades. The Landsat archive is perfectly timed to capture many different waves of colonization across the Amazon.
[Tasso Azevedo] It's very powerful in this sense because it's not just an image. It's actually a bunch of information. What happens with Landsat is that it has several bands which have specific information. So pixel by pixel you have at least seven pieces of information that can be combined in different ways to see different things. So if you are interested to see vegetation there is one combination that you make that can give you more information about vegetation.
[Doug] Landsat satellite data are the most important source we have about how much deforestation happens each year across the Amazon.
40 years ago we see small-scale deforestation creating roads that look like fish bones into the forest. But by the middle of the Landsat record, we see large-scale commodity production taking hold. So today's deforestation across the Amazon frontier isn't a single-family, it's tractors and bulldozers clearing large swaths of rainforest to make room for industrial-scale cattle ranching and crops. So far the amount of area that's been deforested in the Brazilian Amazon alone is equivalent to the size of the state of California.
Deforestation in the Amazon happens with fire. Today's deforestation looks like the large-scale clearing of swathes of rainforest, using heavy machinery; and then the land is burned and burned again to remove all of the tropical trees and timber. If we think about the sizeof a soccer field, we think about deforestation in those same size categories. So deforestation in the early part of the Landsat record might have been numbered in a single soccer field. Today's deforestation happens in tens if not hundreds of soccer fields.
The value of the Landsat archive is that we have a long-term memory of the changes that have occurred across the Amazon frontier. And the MapBiomas record of land cover across the Amazon is an excellent example.
[Tasso] So MapBiomas is a network, formed by NGOs that works with science universities and startups in technology. Our mission is to map and monitor everything that is related to land cover, land use in Brazil, always with a historical perspective.
Because back in '75, 0.5% of deforestation, less than one percent. In '88 was 5% and now we are getting close to 20% of deforestation in the Amazon. You know between 20% and 25% what the science is saying that it's maybe the point of no return. And that's very fast, right? 40-45 years to lose 20% of the Amazon.
So we could precisely identify how many events of deforestation happen in Brazil, or what's the size, who is responsible, what is the piece of land that is there, if they have an authorization or not. And we find out that over 99% of all the deforestation that happened in Brazil in 2019, it was illegal. It's really kind of a striking information that make us to move and say, "Okay we can't accept, we just simply can't accept that we live on a place where the illegality is actually the norm." Right? So this is like the type of thing that we want to kind of use the remote sensing data to kind of shake in the decision-making process of the different agencies in the public and in the private sector. To make better decisions for what we call the stewardship of the management of our natural resources which are crucial for all reasons in Brazil.
The advantage of Landsat. First, it's free. That's absolutely crucial for us. Second, isthat there's no other sensor, not even with lower resolution, or high resolution, that will have a history consistent over the time for 35 years of image available. So, if you really want to havea long history of understanding of any process in the Earth, Landsat is where you shouldgo.
[Doug] Without Landsat we would not have the record we have today, about deforestation, and changingagriculture across a vast and important biome. We anticipate the launch next year of Landsat 9, which will carry on the legacy of this data record, allows us to go back in time, and understand how our planet has changed over 40 years.
[NASA logo] USGS science for a changing world.
Landsat is a joint program of NASA and USGS