The GEDI mission promoted by the Goddard Space Flight Center in NASA (American Space Agency) and the University of Maryland, in USA, uses an instrument on the International Space Station (ISS) to search for and map forested areas around the world. Among the main tasks are studying the characteristics of vegetation, predicting how much carbon these conglomerates of trees store and what the impact of deforestation on combating climate change.
GEDI is short for Global Ecosystem Dynamics Investigation. This mission, which has been ongoing since 2019, emits laser beams that measure the height of trees and the structure of the analyzed forests. The device, designed for the mission, is docked to one of the ISS modules, has the dimensions of a refrigerator and weighs about 500 kg.
Read more:
One of the members of the GEDI science team, Spanish scientist Adrian Pascual, an expert in the field of mapping and forest ecosystem management and a professor at the University of Maryland, explained how the measurement takes place. “When this pulse of energy reaches the Earth, it hits the first element it hits, which is the tops of the trees, and keeps advancing until it hits the ground.”
To unravel the composition of forests, GEDI researchers are studying changes in the structure of energy waves captured by a laser using LIDAR technology, which consists of aiming a laser at a surface and measuring the time it takes for it to return to its source, from which levels of vegetation and their structural structure can be distinguished. complexity. This technology is not new and has never been tested for forest monitoring.
One way to determine the amount of carbon in forests is to check the biomass of trees, Pascual says, about 50% of a tree’s biomass is carbon. “It is more or less estimated that a medium-sized tree, the most typical tree imaginable, holds about 25 kg of carbon dioxide per year.” Based on GEDI, the stock and storage of carbon that currently exists in all the world’s forests is estimated.
In Brazil, for example, the scientist continues, “there are areas of the Amazon and remote places where we don’t know how tall the trees are and how the biomass is distributed.”
GEDI data and maps are publicly available and are needed by governments to really know what is the capacity of forests in their area to store carbon and what is the impact of government policies that intervene in this issue, since changes can also be determined. as a result of forest fires or illegal logging.
Save or plant new species?
GEDI data shows that the conservation of mature forests should be as much a priority as the planting of new tree species. “In order for many small trees to replace the carbon that a very large tree has accumulated, it takes many small trees, time, and so that during this time there are no such phenomena as cutting down, fire or pest attacks,” Pascual comments.
The scientist warns that people should not fall “into the trap of thinking that we can replace large carbon stocks, like the Amazon, which stores a lot of carbon, with plantations and restoration projects.”
One of the limitations of GEDI is the measurement of carbon content underground, in the roots of trees. Carbon in forests is not only above ground, it is estimated to be almost twice as much as a laser system can predict.
There is a movement of researchers and government representatives who support the campaign to extend the life of GEDI in space. One scientist not on the mission but using their data is Flavia de Souza Mendez. For her, GEDI plays a critical role in climate change mitigation.
“Climate change will affect more people and countries from underrepresented and low-income groups. Free GEDI data can help inform policy and research in low-income countries,” says Mendes.
On the other hand, “the carbon market is very hot right now and there are many companies emerging that are calculating the carbon stored in the forest or in reforestation and forestry projects to sell carbon credits.”
Developing GEDI and understanding how the technology works from the space station took nearly 20 years of upfront work. Researchers have conducted numerous scientific studies. However, the mission is only scheduled to operate until the end of 2023, when GEDI will be replaced by another instrument on the International Space Station.
By using: BBC news
