There has been so much mind-numbing stuff happening, like Government Shutdowns, that I overlooked the launch of a very important NASA Earth Science mission recently. On December 5, 2018, NASA launched the Global Ecosystem Dynamics Investigation (GEDI) Lidar to the International Space Station (ISS). By the way, NASA does pronounce the acronym like "Jedi" from the Star Wars. What is this mission and does it have the "force" to help save the Earth's forests.
A NASA website points out that "GEDI uses LIDAR to provide the first global, high-resolution observations of forest vertical structure." In Star Wars, the light saber is a powerful light-based weapon so I suppose we can say NASA has its own (sorta). I will take more of a deep dive momentarily, but it is important to make sure that you understand what LIDAR is. The Remote Sensing Branch of NASA describes LIDAR this way:
LIDAR is the optical analogue of RADAR (RAdio Detection And Ranging). The only thing that separates LIDAR from RADAR is the energy source. LIDAR’s source being a laser in the optical part of the electromagnetic spectrum. LIDARs are active remote sensors since they include the light source on which the measurement depends.
From aircraft or spacecraft, NASA and other scientific organizations have exploited the capabilities of LIDAR for decades to study clouds, pollution, wind, temperature, and characteristics of the Earth's landscape. Some readers (pleading the 5th here) may have received a speeding ticket from a police officer using laser-based detection devices.
I always introduce the "so what" factor when writing about innovative science or technology. Why does the GEDI mission matter and what does it hope to accomplish? Ralph Dubayah, the GEDI Principal Investigator and Geographical Sciences professor at the University of Maryland, said in a 2018 NASA press release,
Scientists have been planning for decades to get comprehensive information about the structure of forests from space to deepen our understanding of how this structure impacts carbon resources and biodiversity across large regions and even globally, as well as a host of other science issues.
From the low-earth orbit perspective of the International Space Station, GEDI will detect pulses of light that are reflected off the Earth's tropical and temperature forests producing very detailed, three-dimensional analyses. GEDI scientists hope to fill gaps in our understanding of how much carbon is stored in the Earth's forests and how ecosystems will handle increasing amounts of carbon dioxide in the atmosphere. The mission may also provide inside on how changing forests affect biodiversity.
Most of us learned about the water cycle in elementary school. My 6th grader can rattle off the components with ease. I challenge you to pause and consider when (or likely if) you learned about biogeochemical cycles such as carbon or nitrogen. The diagram above represents the carbon cycle. Forests are critical "sinks" for atmospheric carbon dioxide and why scientists are concerned about the loss of them. They use carbon dioxide from the atmosphere for photosynthesis.
Carbon dioxide values continue to rise sharply (graphic below) and it may be tempting to conclude that will see more vegetation to remove excess amounts. The NASA Earth Observatory website provides perspective:
In high and mid-latitudes, abandoned farmland is reverting to forest, and these forests store much more carbon, both in wood and soil, than crops would...In the tropics, however, forests are being removed, often through fire, and this releases carbon dioxide. Carbon dioxide increases temperatures, extending the growing season and increasing humidity. Both factors have led to some additional plant growth. However, warmer temperatures also stress plants. With a longer, warmer growing season, plants need more water to survive.
Deforestation may account for as much as 10-20% of human carbon emissions, which makes the GEDI mission so important for accounting. The 2017 paper at this link was published in Nature and is excellent starting point for a scholarly perspective on forests, land use, and carbon emissions.
For more information on the mission, visit this website.
