How Lasers Can Help Save the World’s Forests | Fast Company
The destruction of forests ranks as the second leading cause of climate change – after the burning of fossil fuels — accounting for up to 20 percent of global carbon pollution. Recognizing this connection last December in Cancun, the countries of the world established the ground rules for a mechanism known as REDD — reducing emissions from deforestation and forest degradation.
REDD works by recognizing and quantifying one of the great values of standing forests: removing and storing harmful carbon pollution. If a country can show that it has reduced its level of deforestation (and the related carbon pollution), then it will receive payments. These payments could come from other governments or from corporations looking to reach climate goals.
Great idea, but only if you can accurately draw up a balance sheet of carbon-in, carbon-out. No one in their right mind would put money into a market with a broken ticker. Until recently, measuring carbon has been too complicated, too costly and altogether inaccurate.
An unlikely solution: lasers being shot from planes at 200,000 photons per second. In a nutshell, that’s LiDAR—Light Detection and Ranging.
It’s not impossible to collect forest structure data by measuring trees on the ground. But anyone who has spent some time on the forest floor in, say, the Peruvian Amazon, can attest to how tough that is. It’s not the venomous snakes, aggressive insects, and oppressive heat that are necessarily the issue. Try to put a tape measure around a tree whose diameter doesn’t even come close to a circle, or one with flaring, head-high buttresses that ward off even the most accomplished tree-climbers. Try and estimate height amidst throngs of choking lianas where each tree disappears into a cacophony of green several hundred feet up in the air. It’s not impossible, but it certainly isn’t easy, fast or cheap.
With LiDAR, we can calibrate aerial images with a smattering of ground plots administered by scientists. The results are calculated to create an algorithm that enables you to use satellite imagery not just to count the trees, but also the carbon they contain. A year and a half ago, we flew with the Stanford University Carnegie Airborne Observatory’s Greg Asner over those very impossible-to-measure forests of the Peruvian Amazon and mapped the structure of 11 million acres in 3 weeks. That’s a structural analysis of a forest down to one meter for an area the size of Switzerland—and completed for just a few cents an acre.