Satellite observations and climate's impact on Earth

Expanding the boundaries of the universe, man continues to turn his gaze towards the stars. This path, charted by thinkers, scientists and, of course, science fiction writers, has attracted mankind for centuries. It has always been a challenge, thorny and competitive, but man is a fantastic particle of the cosmos, always moving forward, discovering it, conquering it and turning it into his own home. Space programmes require more and more resources, which are now too much for individual countries, even the largest ones. This drives them to international cooperation in both near and far space. Space agencies such as ESA, NASA, etc., are opening a new chapter in global climate research, launching integrated monitoring projects to develop effective policies in tackling the climate crisis and solving environmental problems. The long-term programme includes a series of exploratory space missions: Earth Observations (OT).

According to the UNEP Report, "the world finds itself at the epicentre of a triple planetary crisis linked to climate change, biodiversity loss, pollution and waste. The path to sustainable development becomes steeper and narrower as the window of opportunity closes'. The Earth is an extremely complex system that reproduces itself through a unique balance, the imbalance of which could cause irreversible processes of planetary ecosystem destruction. According to the last European Information Bulletin 2024, 2023 was the hottest year ever; biological communities are becoming more and more homogeneous, leading to a decrease in biodiversity and the extinction of many species; in the last 50 years, there has been an irreversible increase in direct and indirect anthropogenic factors affecting the biosphere. The significance of climate change and its impact on the planet's biodiversity is frighteningly obvious.

Satellite observations (OS) are the process of analysing the Earth by means of remote sensing, which consists of measuring electromagnetic radiation from the Earth and the atmosphere. Depending on the instruments, satellites conduct passive or active sensing. In passive mode, they measure the earth's own radiation or reflected sunlight in the visible or infrared spectrum. In active mode, they scan the area with radar (microwave or laser radiation) and receive a reflected signal to measure the height of vegetation, depth of glaciers, sea level. EO (Earth Observation) satellites are divided into orbital and geostationary. Orbital ones follow polar orbits at low or medium altitude, covering the entire surface of the Earth, while geostationary ones are about 35,786 km above the Earth's equator and appear to be stationary in the sky as they move at the same angular velocity as the Earth.

Satellite observations (OS) through tele-sensing (TR) include climate monitoring, weather forecasting, the study of changes in ecosystems and the atmosphere and their impact on each other. In particular: Atmosphere: temperature, pressure, greenhouse gas content; Oceans and Seas: water temperature, currents, sea level; Glacial ice caps: changes in glaciers and melting level; Soils and Vegetation: soil conditions, vegetation, forests; Cities and anthropogenic changes, environmental impact; Air pollution: composition, concentration of pollutants; Anomal events: hurricanes, droughts, floods; Biodiversity: monitoring the diversity of living organisms and ecosystems. These lines of research provide a comprehensive view of the state of our planet and its changes. Six of these areas have also become priorities in the Copernicus missions and form the basis for the OS.

OS technology has evolved greatly in the sixty years since the launch of the first Sputnik-1 satellite into low Earth orbit in 1957 with a simple radio transmitter on board. Advances in science, telecommunications, and the development of new remote sensing techniques, such as passive multi- and hyperspectral instruments, as well as LiDAR and active synthetic aperture radar (SAR) sensors, has allowed satellite missions to be adapted over the years to a broader range of applications to tackle increasingly complex tasks. The environmental satellite of the ESA (Envisat), launched in 2002, carried many different sensors, providing a wide range of key data on oceans, land, atmosphere and cryosphere. ESA has already developed and deployed the Sentinel family of OS satellites to support the Copernicus project, which is Europe's most ambitious programme to date. One curiosity is the introduction of artificial intelligence AI in satellite tracking programmes.

The scientists at the University of Leeds have presented a neural network that can quickly and accurately detect large Antarctic icebergs on satellite images in just 0.01 seconds. This new method greatly improves existing laborious processes. Using the radar Copernicus Sentinel-1, satellite data are transmitted to artificial intelligence for analysis and mapping of icebergs. Due to their fusion with the surrounding white terrain, it is difficult to define the exact contours of the icebergs. However, AI copes well with this challenge by adapting its algorithms. Its architecture is based on the U-net design, and training takes place on different Sentinel-1 data. After automatic parameter correction for optimal performance, the system achieves 99% accuracy.

The OS plays an important role in the study and management of ecosystems and biodiversity. The Landsat satellites, veterans of EO since 1972, are a series of high-resolution satellites launched by NASA. Their innovative technologies make it possible to monitor plant health, population density, species migrations and the state of biodiversity. The integration of Landsat data with ground-based sensors makes it possible to study the dynamics of ecosystems in space and time and to make decisions for land management and nature conservation. Since its initial launch, Landsat has conducted several missions that provide a continuous stream of data. With a trio of smaller satellites each capable of detecting 26 different wavelengths, the Landsat Next mission is radically different from its predecessors in 50 years of OT.

The researchers from Griffith University found that less than 13% of Australian possum habitat in Queensland is on the brink of extinction due to heavy rainfall and forest fires. They used Landsat remote sensing data to map forest cover, GEDI lidar data to map forest height, and GlobBiomass data to assess forest density and biomass. The satellite data helped to create a map of forest characteristics and maturity to identify areas favourable to possums. The results of the research were reported to the Queensland government and were instrumental in taking steps to expand protected areas and conserve biodiversity in order to protect possums and other animal species.

Protecting our planet and its atmosphere is a top priority. To this end, a number of satellite missions (led by EUMETSAT, ESA and NASA) have been launched, aimed at monitoring and protecting all forms of life on Earth, as well as studying atmospheric, climatic and ecosystem changes. Here is a brief overview of some of the operational missions: Meteosat second and third generation geostationary satellites; NASA's new Landsat Next mission; ESA Vigil missions: observation of the Sun; Copernicus mission: from Sentinel-2 to Sentinel-6; GOCE: ESA gravimetric mission; SMOS: ESA mission on water; CryoSat: ESA mission on ice; Swarm: ESA mission on magnetic field; Aeolus: ESA mission on winds; EarthCARE: ESA mission on cloud and aerosol observation; Biomass: ESA mission on forests; FLEX: ESA mission on photosynthesis.

3Bee's scientific approach to assessing the impact on biodiversity allows for a preliminary assessment of the biodiversity present in the area (Biodiversity Site Assessment). The analysis combines data from Sentinel I and II satellites, satellite analysis and information from public databases, and enables the generation of synthetic indicators that reflect the current state of biodiversity and the area's capacity to support wild pollinators. Based on these results, site-specific interventions are planned and strategies are formulated to regenerate biodiversity.