It's a pretty map detailing an ugly reality: global forest loss.

A team from the University of Maryland has created an interactive look at 12 years-worth of satellite data on forests cover. The Global Forest Change map is the first high-resolution map of worldwide forest loss and gain. And according to their research, the former has outpaced the latter by a significant margin: a global loss of 2.3 million square kilometres (shown in red) and a gain of just 800,000 square kilometres of new forest (shown in blue).

“The human footprint on the Earth is really amazing,” says Dr. Matthew Hansen, who heads up the university team that developed the map. “The rates of change are incredible. If you're a tree-hugger, these data have meaning. If you're a logger, they have meaning.”

For Hansen, the map presents the unique opportunity to study both global forest trends and localized disturbances in tree cover. Anyone sitting at home with a computer can zoom right in on their city or town and discover how the trees in their area have fared between 2000 and 2012.

“We see a whole ridge of a mountain range in China where the Sichuan earthquake literally shook forests off the slopes and into the valley,” Hansen says as an example, referring to the devastating earthquake of 2008.

On a larger scale, the data show forest loss increasing in the tropics by over 2000 square kilometres each year. Hansen hopes this kind of information will spur governments to change their policies regarding deforestation. Or, at the very least, prompt countries to be more forthcoming with their own data on forest cover and loss.

The university team based the map on 650,000 images from the Landsat 7, a NASA satellite. They then consolidated the portraits of the Earth into one map — a potentially daunting task given the shear load of information to distil. And that's where Google came in. Using Landsat data and Hansen's team's algorithms, the tech giant was able to process the map.

“What one computer could do in 15 years, their Google Earth Engine could do in days,” says Hansen.

The plan for the map going forward is to update it annually. Eventually, Hansen says, he'd like to report changes in forest cover in as close to real time as possible.

“If a logging road goes into a national park why should we wait a year for people to know about it?”

He chuckles at the suggestion that this will be a lot of work.

“You can't be afraid of data volume. If the data are there we have to use them.”

Tips for navigating the Global Forest Change map:

  • The drop-down menu under the heading “Data Products” allows you to focus the map on different aspects of the data.
  • For example, select “Forest Cover Loss 200-2012” if you want to view only forest loss from the past 12 years.
  • The map's default view does not display place names — but there’s an easy fix. You can change the transparency of the data overlay by sliding the round black button under the drop-down menu. The farther the button is to the left, the more clearly you can see the location markers on the map.
  • The creators of the map have plugged in a few locations that show forest loss and gain quite dramatically on a local scale. Just select one from the “Example Locations” drop down menu and click “Zoom into area” to view them.
  • If you have changed the settings of the map beyond recognition, you can get back to the original look by clicking “Reset to default view.”