Deforestation visualized

Nieuws | de redactie
6 december 2013 | “We know forests are shrinking, but knowing exactly where and by how much often means compiling locally reported data that can be shoddy, incomplete, or outdated,” says geographer Matthew Hansen. With a new tool he found out that the world lost a forest the size of Algeria, in the last twelve years.

A large shortcoming for many foresters, climate scientists and policy makers is the lack of detailed data on deforestation. Matthew Hansen from the University of Maryland, partnered with Google earth to create the most high-resolution map of forests ever made, consisting of over 650.000 images taken by NASA satellites since 2000.

Algerian sized forest

The result, is a stunning series of time-lapse maps, along with an interactive mapping tool, that reveal the Earth lost about 2.300.000 square kilometer of forest between 2000 and 2012, a size comparable to Algeria.

The loss of forest cover has been most dramatic in the tropics. Logging, urban development, mining and roads are the most important causes, Hansen explained. Not all forest loss was directly caused by humans. Fires and earthquakes contributed as well. The maps are accurate to 28 square-kilometer units, close enough to see logging roads and individuals stands of trees, which gave the researchers an unprecedented look at the complete extent and rate of deforestation on a global and hyper-local scale.

15 years’ worth of calculations

Partnering up with Google accelerated the pace of the research, or –maybe even more accurate – made the research possible. Hansen estimated his own computer would have taken 15 years to process all the images, while Google’s supercomputers produced them in a few days. 

The data could be used to track the impact of forest protection policies, new roads and give insights on the latest developments in areas that are most endangered. “It’s a big leap forward in terms of a set of facts, a set of observations on what this dynamic is,” Hansen said.

One of the next steps, Hansen said, is to use the data to gauge exactly what this deforestation means for climate change. Trees are one of the largest “sinks” for carbon dioxide; previous studies suggest forests absorb a third of the carbon released by burning fossil fuels.

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