A View from Space Can Save the Trees
For government agencies and conservation groups, protecting forests can be a tall order. Their resources often don’t allow them to cover the sheer amount of acreage they need to monitor, and there are a lot of places to conceal damaging and illegal activity.
But it’s hard to hide destructive practices from eyes in space.
That’s the idea behind GLAD, the Global Land Analysis and Discovery system. Launched in 2016, GLAD uses satellite-acquired data to provide frequent, high-resolution alerts when it detects a drop in forest cover. Governments and others interested in halting deforestation can subscribe to the alerts on the free and interactive interface called Global Forest Watch and then intervene to limit forest loss. And it seems to be working, at least in one part of the world.
According to research led by Fanny Moffette, a postdoctoral researcher in the Department of Agricultural and Applied Economics and the Nelson Institute for Environmental Studies, deforestation dropped by 18% in two years in African countries where organizations subscribed to receive forest cover warnings from GLAD. And the carbon emissions avoided by reducing deforestation were worth between $149 million and $696 million, based on the ability of lower emissions to reduce the detrimental economic consequences of climate change.
The researchers — including Moffette’s collaborators Jennifer Alix-Garcia at Oregon State University, Katherine Shea at the World Resources Institute, and Amy Pickens at the University of Maryland — studied deforestation in 22 tropical countries across South America, Africa, and Asia from 2011 to 2018. They set out to understand whether these kinds of automated alerts could achieve their goal of reducing forest loss, which has global climate implications. Land-use changes such as deforestation account for 6–17% of global carbon emissions. And avoiding deforestation is several times more effective at reducing carbon emissions than regrowing forests.
“The first question was to look at whether there was any impact from having access to this free alert system,” Moffette says. “Then we were looking at the effect of users subscribing to this data to receive alerts for a specific area.”
Simply being covered by GLAD did not help a country combat deforestation. Only those African countries in which organizations had actually subscribed to receive alerts saw a decrease in deforestation. Intuitively, this finding makes sense, says Moffette. Having access to information is good. But what you need to change the course of deforestation are people committed to using that information and acting.
However, deforestation did not decrease in South American or Asian countries, even where organizations subscribed to receive warnings. There are multiple potential causes for this continental discrepancy.
“We think that we see an effect mainly in Africa due to two main reasons,” Moffette says. “One is because GLAD added more to efforts in Africa than on other continents, in the sense that there was already some evidence of people using monitoring systems in countries like Indonesia and Peru. And Colombia and Venezuela, which are a large part of our sample, had significant political unrest during this period.”
The GLAD program is still young, and as more governments and organizations sign on to receive warnings and decide how to intervene at sites of deforestation, the system’s influence may grow.
Developed by a team at the University of Maryland, which includes Pickens, GLAD made several improvements over its predecessors. It has very high spatial resolution, roughly 900 square meters, which is orders of magnitude more precise than older tools. And it can provide alerts up to every eight days if the skies are cloud-free when satellites reimage a section of Earth. Users can define custom areas to monitor. They then receive weekly emails, available in six languages, that contain geographic coordinates of the alerts within the monitored areas.
Going forward, the team is looking to evaluate the effect of the monitoring platform’s new features, such as data that can inform forest restoration, while supporting efforts of organizations that try to intervene to halt deforestation.
“Now that we know subscribers of alerts can have an effect on deforestation, there’s potential ways in which our work can improve the training they receive and support their efforts,” Moffette says.
Findings from this study were published in January in the journal Nature Climate Change.