Will a malfunctioning satellite spell trouble for forests?
2 février 2022
These days, Brazil is not the first country most people would go to for lessons on stopping deforestation and violations of Indigenous Peoples’ rights, but it has perhaps the most impressive deforestation-monitoring system in the world. In December 2021, Fern released a new report looking at what a proposed EU deforestation observatory could learn from Brazil. Just days after its release, Copernicus Sentinel-1B, a very important satellite for observing deforestation, went dark.
Fred Stolle of the World Resources Institute outlined what the malfunction means for forests and the EU. He started by explaining how satellites are used to monitor deforestation:
“Because forests are remote and difficult to measure, satellite monitoring from the National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA) has been revolutionary. It is particularly impressive that they give their data absolutely free, NASA since 2008 and ESA since 2016. It used to cost about USD 10,000 for one image, and now you can download as many as you like and just use the best bits. What once took five years to report, now takes 10 days.
It’s important to remember that they are monitoring loss of tree cover – to map deforestation you need to know what is making the trees disappear, and that requires on-the-ground knowledge.”
Q: You use RADD Forest Disturbance alerts. What are they and how do they help?
“There are different kinds of satellites, Sentinel 2 is an optical satellite using visible and infrared light. Sentinel 1 is a radar satellite. RADD stands for Radar for Detecting Deforestation, meaning that you can see through clouds, which is particularly important in wet areas (such as in Indonesia or Gabon) that are so often covered in cloud. Two Sentinel 1 satellites (A and B), together, allow a weekly picture of what is happening in the forest. They alert you to possible changes and then you can go and investigate on the ground. Of course, even radars can’t see everything, such as what happens below overlapping canopies where smaller trees grow below taller trees. They also can’t tell you why the tree has gone, though they can spot logging roads, which give you a good idea. This is why it’s so important to work with local people.
Q: How does the EU use satellite data?
Until now, the EU has to my knowledge not used its data for any law or Regulation, but the Joint Research Centre is now tasked with developing an EU Forest Observatory that might change that [as well as a new regulation on Forest monitoring, as foreseen in the EU Forest Strategy]. Co-operation between ESA and the EU is good. ESA develops and launches the satellite and makes the data freely available, and EU Copernicus provides funds to private companies that then develop services and maps, and analyse the data so that it is useable for the public.
Q: Is the loss of Sentinel-1B likely to have a real impact on the ground?
The Sentinel satellites are really important for wet areas such as in South East Asia and the Congo Basin. They used to give a picture of what was happening there every six days, but with the loss of 1B it will now be every 12 days, hampering those who rely on that data to know where to patrol. This is a problem, but not a disaster, and that is because the ESA really thought about the future. Sending up two satellites is so much more powerful than sending one.
Q: What can be done?
The ESA is trying to mend 1B, but if that doesn’t work, Sentinel 1C is almost ready to go up. The foresight of ESA of sending up two satellites that do exactly the same thing has now really paid off.