Satellites Are Being Used to Send Alerts When Deforestation is Detected

Deforestation carries with it serious consequences for the economy, the environment, wildlife, and communities that rely on forests for income. A newly updated tool has given governments and organizations a way to keep an eye on trees so they know when anyone has been illegally cutting them down.

The Global Land Analysis and Discovery system provides frequent alerts about decreases in forest cover through the free, interactive web interface Global Forest Watch. Anyone can sign up for the updates, though they are especially beneficial for local governments. The information is provided by satellites, which circle back to each spot on the globe about once a week.

Mikaela Weisse helps the run the Global Forest Watch site. She told NPR, “If we can detect deforestation and other changes as soon as they’re happening, then there’s the possibility to send in law enforcement or what have you, to stop it before it goes further.”


There have recently been upgrades to allow for cloudy days, as well. This is important because Weisse says some loggers and ranchers used prolonged rainy periods to cut down trees. Now, the system uses radar from satellite sensors operated by the European Space Agency, which delivers sharper pictures and sees through the clouds.

Weisse explains, “Essentially, the satellites are sending radio waves to Earth and collecting how they come back… We can actually see these little patches that indicate where there’s been removal of a single tree.”

A recent study shows how effective this technology has been in Africa. Fanny Moffette, a postdoctoral researcher in applied economics at the University of Wisconsin-Madison, led a team of researchers to determine whether these alerts actually help decrease deforestation. Their results were published in January in the journal Nature Climate Change.

The researchers examined deforestation in 22 tropical countries in South America, Africa, and Asia between 2011 and 2018.


Moffette explains, “The first question was to look at whether there was any impact from having access to this free alert system. Then we were looking at the effect of users subscribing to this data to receive alerts for a specific area.”

The team found that deforestation decreased by 18% in two years within African countries that subscribed to the service. This lowered the cost of carbon emissions by between $149 million and $696 million, based on the lower emissions’ ability to reduce the economic impacts of climate change. However, only those who subscribed to the service saw these benefits. Moffette says though having access to this information is important, things will only change if people are committed to using that information and then acting on it.

The study did not show any sizable impacts in South American or Asian countries, even those in which organizations subscribed. There are some theories from the researchers as to why.

Moffette explains, “We think that we see an effect mainly in Africa due to two main reasons. One is because GLAD added more to efforts in Africa than on other continents, in the sense that there was already some evidence of countries 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.”


To try to increase usage and improve the system, the team now plans to look into how new features like data on forest restoration are having on the monitoring platform. They also hope to encourage efforts by organizations that are fighting deforestation.

The World Wildlife Fund says threats to forests are primarily due to agriculture and illegal logging. In the tropics, close to 30 soccer fields’ worth of trees were lost every minute in 2019. This puts the livelihoods of millions of in jeopardy, as an estimated 13.2 million people throughout the world have jobs in the forest sector and another 41 million work in a field related to the sector. Eighty percent of the world’s land-based species also live in forests. This is in additional to the environmental benefits of trees, including their role in absorbing carbon dioxide.

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Moffette says now that they know their service can help decrease deforestation and address these impacts, they know they can help improve their subscribers’ training and support their efforts. They also hope the program can continue to grow and become more effective at helping address these issues in other countries.

If you’d like to check out the service yourself, visit its website.

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