We’re excited to announce today that, in a collaboration led by Dr. Matthew Hansen at the University of Maryland, we’ve built the first detailed maps of the world’s forests, from 2000-2012, documenting and quantifying forest landscape changes such as fires, tornadoes, disease and logging.

The most significant findings were that the overall rate of tropical deforestation is increasing, and global forests have experienced a net loss of 1.5M sq km during 2000-2012 due to both natural (disturbance) and human causes. That’s a loss of forested land comparable in size to the entire state of Alaska.

Global Forest Change, 2000-2012: individual maps of forest extent, gain, loss, and loss color-coded by year. Click to enlarge.

Sumatra has lost over 50% of its natural forest within the past 30 years. Click to enlarge.

The detailed study was published today in the journal Science, High-Resolution Global Maps of 21st-Century Forest Cover Change. Key to the study’s success was the collaboration between scientists at the University of Maryland, who developed the models to analyze Landsat satellite data, and computer scientists at Google, who then used Google Earth Engine technology to run these models on more than 650,000 Landsat images. While the analysis would have taken a single computer more than 15 years to perform, it was completed in a matter of days using Google Earth Engine.

Here are some other notable sites:

Paraguay’s Chaco woodlands within the western half of the country are experiencing rapid deforestation in the development of cattle ranches. The result is the highest rate of deforestation in the world. Click to enlarge.

The Siberian larch forests of Yakutia, Russia, are prone to fire during spring to early summer. Most of these fires are deliberately set and spread uncontrolled. Such extensive fires result in significant carbon emissions. Click to enlarge.

If you'd like to dive even deeper and learn more about this project, head on over to the Google Research blog post authored by Dr. Matt Hansen. Also, tune in next Monday, November 18 at 1:00pm ET, 10:00am PT to an online presentation and demonstration by Matt Hansen and colleagues from UMD, Google, USGS, NASA and the Moore Foundation. Please submit your questions for live Q&A.

Updated 3:30pm PDT: Corrected total sq km of net loss during 2000-2012.