A shower of laser pulses is currently coming to Earth from the International Space Station.

And its purpose is to uncover even the most intimate secrets of the planet’s forests.

The GEDI mission, jointly developed by NASA’s Goddard Space Flight Center and the University of Maryland, Get unprecedented 3D maps of forest areas even in the most remote locations.

“This is a satellite the size of a refrigerator, weighing about 500 pounds, and attached to or attached to one of the modules of the International Space Station,” said Spanish scientist Adrián Pascual, an expert and a member of the GEDI science team. BBC Mundo. Professor in the mapping and management of forest ecosystems and at the University of Maryland.

Mission data is critical to understanding how much carbon the forest stores and what impact does deforestation have on the fight against climate change.

But GEDI’s future is uncertain, and a campaign is currently seeking to ensure continuity of the mission.

How does GEDI work?

GEDI is the English abbreviation of Global Ecosystem Dynamics Investigation or Research on the Global Dynamics of Ecosystems.

The heart of the program is an instrument that shoots lasers and has been attached to the International Space Station, the ISS, since 2019.

“The ISS is constantly making orbits over the Earth. And our GEDI satellite is always emitting laser pulses,” Pascual said.

These energy pulses allow to identify not just the height of the trees, but the structure of the forests.

“When this energy pulse reaches Earth, it hits the treetops, the first element it finds, and continues to advance until it hits the ground.”

“The sensor measures the difference between when it detects the tops of trees and the ground. Y By converting this time to distance, we can estimate the height of the vegetation.”

GEDI researchers are studying changes in energy wave patterns to reveal the forest’s composition.

“We can predicting different vegetation levels and this gives us an idea not only of the height of the forest, but also of its structural complexity».

GEDI uses a remote sensing technology called LIDAR, which basically consists of aiming a laser at a surface and measuring the time it takes for it to return to its source.

It is not a new technology. “However, this technology was never placed on a satellite and taken to the International Space Station, and was not applied specifically to monitor forests at an altitude of more than 400 km,” Pascual says.

Carbon: basic data

Trees capture CO2, or carbon dioxide, from the atmosphere, one of the main greenhouse gases responsible for climate change.

And they store most of this carbon, preventing it from being released into the atmosphere.

“When trees grow, they increase their biomass. Y About 50% of the biomass of the wood of these trees is carbon,” Pascual said.

“A medium-sized tree is roughly calculated to fix about 25kg of carbon dioxide per year, the most common thing to think about.”

“Then we use GEDI to know what the stock, the carbon store, is in forests all over the world right now.”

GEDI’s role in tackling climate change

Data and maps produced from GEDI are publicly available.

And they are vital for governments around the world to realistically know their carbon storage capabilities.

“As far as many ecosystems are concerned, it’s unknown how tall the trees are or what the forest looks like,” Pascual said.

“There are areas in the Amazon or in remote places where we don’t know how tall the trees are and how the biomass is distributed.”

GEDI makes it possible to detect and measure biomass changes resulting from forest fires or illegal logging.

GEDI data also protect the mature forests of the worldrather than just prioritizing new forest plantations.

Many countries include planting trees in their CO2 emission reduction plans.

“It is true that more trees need to be planted as part of solutions to combat climate change, through restoration projects in degraded areas and with the potential to return to vegetation,” Pascual said.

However, “for many small trees to replace the carbon stored by a very large tree, it takes many small trees, time and no event in the middle like a knockdown, fire or pest attack.”

“We can’t fall into the trap of thinking we can replace large carbon stocks with plantations and restoration projects, like in the Amazon, where large amounts of carbon are stored.”

Carbon stored in forests is not just found above ground.

“Beneath, in the roots of trees, the amount of carbon can be almost twice what we can predict with GEDI. It is therefore vital to protect the ‘lungs’ of the Planet».

Campaign to save GEDI

It took nearly 20 years of previous work to develop GEDI and understand how its technology works from a space station. Numerous scientific studies have been conducted by researchers such as GEDI principal investigator and University of Maryland professor Ralph Dubayah.

The mission is scheduled to be operational by January 2023, when GEDI will be replaced by another instrument aboard the International Space Station.

Both researchers and government representatives They are currently supporting a campaign to extend GEDI’s life in space.

One of the scientists who was not part of the mission but used its data is Flávia de Souza Mendes, a German-based Brazilian scientist and a member of the RSATE (Applied Remote Sensing Applied to the Tropical Environment) research group.

For Mendez, GEDI plays a crucial role in mitigating climate change.

“Climate change will affect more people and countries than underrepresented and low-income groups. Free GEDI data can make a difference in supporting policy making and research in low-income countries.”

On the other hand, “the carbon market is very hot right now and many companies are emerging that calculate carbon stored in the forest or in afforestation and afforestation projects to sell carbon credits.”

Adrian Pascual told BBC Mundo: “There is strong pressure from the international community for GEDI to continue for longer. Because every week it’s there, we have thousands and thousands of observations that allow us to get better estimates of the height of vegetation and biomass».

“It’s a huge opportunity if we can hold it for a few more months or years because we don’t really know when such a possibility will arise again.”