When a tree falls in the forest these days, it doesn’t just make a sound—it causes a computer program to generate an alert that’s sent out to activists, researchers, and environmental policymakers around the planet. An online tool to map deforestation is applying big-data processing techniques to massive troves of satellite imagery, and in the process it is making possible a new kind of environmental activism.

 

The tool, Global Forest Watch, was launched by the World Resources Institute in February to provide monitoring of deforestation around the world. Users can explore the global map to see trends since the year 2000 and can zoom in to examine forest clearing at a resolution of 30 meters. The tropical zones of the map are refreshed every 16 days, frequent enough to track deforestation hot spots in places like Indonesia and Brazil. Users can also sign up for alerts, which are generated when the system detects signs of illegal logging or slash-and-burn agriculture in the tropics.

 

The site is powered by Google Earth Engine, which crunches image data drawn from several NASA and U.S. Geological Survey (USGS) satellites. Google is developing this platform to host petabytes of Earth science data and to give researchers a straightforward way to use it. “They log on, access all the data, and run their own algorithms,” explains David Thau, the senior developer advocate for Google Earth Engine. Thau and his colleagues work with scientists to develop useful analysis functions, and then they “get out of the way,” he says, and let researchers conduct their investigations. Google Earth Engine is currently available to thousands of research partners, and the company plans a general release down the line.