The 21st century’s biggest challenge is to protect and preserve our home – the Earth – as we know it and as we want our future generations to know. The planet is currently held in a vice-like grip by global warming and climate change. While one may argue that these are naturally occurring phenomena that are part of Earth’s evolutionary mechanism, the two processes have catastrophically accelerated due to human intervention. The impact of climate change and its major contributors can best be understood by the study of the Earth’s forest and wetland ecosystems.
Globally, humanity razes around 10 million hectares of forest every year. When deforestation occurs, much of the carbon stored by trees is released back into the atmosphere as carbon dioxide, contributing to climate change. Other factors such as forest fires, pollution and effluent emissions from industrialisation and the burning of fossil fuels, play their part as well, resulting in drastic shifts in weather patterns and increasing natural calamities.
In a major milestone – for both space technology and climate change research – NASA (National Aeronautics and Space Administration) and ISRO (Indian Space Research Organisation) are collaborating in building and launching the NASA-ISRO Synthetic Aperture Radar (NISAR), which looks to revolutionise research into the forest and wetland ecosystems while explaining their impact on the carbon cycle influencing climate change dynamics.
The NISAR mission will launch an Earth observation satellite in January 2024, which will offer insights into forest and wetland ecosystems – vital to naturally regulating greenhouse gases in the atmosphere that are driving global climate change, according to NASA’s Jet Propulsion Laboratory (JPL).
In orbit, NISAR’s sophisticated radar systems will scan Earth’s land and ice surfaces twice every 12 days, and the data thus collected will help researchers understand the capture and release processes of carbon. “The radar technology on NISAR will allow us to get a sweeping perspective of the planet in space and time,” says Paul Rosen, NISAR project scientist at JPL in Southern California, adding, “It can give us a really reliable view of exactly how the Earth’s land and ice are changing.”
Keeping forests alive
It is known that forestry and other land-use changes account for 11% of net manmade greenhouse gas emissions. However, there is dearth in understanding carbon sources and sinks from terrestrial ecosystems, particularly forests. NISAR’s data will improve understanding of the loss of green cover around the world, and its influence on the carbon cycle and contribution to global warming.
“We expect NISAR to greatly help address that, especially in less-dense forests, which are more vulnerable to deforestation and degradation,” informs Anup Das, co-lead of the ISRO NISAR science team. NISAR will carry a sophisticated L-band radar, whose signal can penetrate forest canopies, bouncing off tree trunks and the ground.
By analysing the reflected signal, researchers can estimate the density of forest cover over an area as small as a football field. With successive orbital passes, it will track whether a section of forest has thinned or been cleared over time.
The data, collected in early mornings and evenings across all weathers, could also offer clues as to what caused the change, such as disease, human activity, or fire. This is a significant step in conserving cloud-covered rainforests such as those found in the Congo and Amazon basins, and Borneo, which lose millions of trees annually.
Wetland wellness
Swamps, bogs, peatlands, inundated forests, lagoons, marshes, mangroves, and other wetlands hold 20-30% of carbon in Earth’s soil, despite making up just 5-8% of the terrestrial surface. When wetlands flood, bacteria digest organic matter in the soil, turning the topographical features into the planet’s largest natural reservoirs of potent greenhouse gas methane, which bubbles to the water’s surface and rises into the atmosphere.
As wetlands dry out, the carbon stored within is exposed to oxygen, releasing carbon dioxide. However, we know very little about the changing temperature and precipitation patterns due to climate change, along with human activities such as agriculture, affecting the flooding in wetlands. NISAR will monitor the flooding, helping researchers track seasonal and annual variations in wetland inundation, as well as long-term trends, informs the JPL.
NISAR’s wetland observations, coupled with data on greenhouse gas emissions, could assist researchers in gaining insights into the management of fragile ecosystems. Space research has been critical in averting major environmental disasters, by helping us study our planet from afar. Space is our future, that is helping us preserve our past and protect our present – the Earth.
