ESA’s Biomass Satellite Launch: A Milestone in Mapping Forest Carbon
On April 29, 2025, the European Space Agency (ESA) achieved a major advancement in Earth observation with the launch of its Biomass satellite, a mission designed to map forest biomass and help scientists more accurately quantify the carbon stored in the world’s forests — crucial players in the fight against climate change.
Lifted into orbit aboard a Vega-C rocket from Europe’s Spaceport in Kourou, French Guiana, Biomass carries a groundbreaking P-band synthetic aperture radar (SAR) — the first instrument of its kind flown in space. Unlike traditional satellites that rely on optical imagery or shorter-wavelength radars, this powerful new sensor can penetrate through dense forest canopies and clouds to gather information about the woody biomass beneath — primarily trunks, large branches, and stems where most carbon is stored.
Why This Mission Matters for Climate and Carbon Tracking
Forests act as one of Earth’s most vital carbon sinks, absorbing significant amounts of carbon dioxide (CO₂) from the atmosphere — roughly 8 billion tonnes annually. However, accurately measuring the amount of carbon forests store has been a long-standing challenge for scientists. Traditional Earth observation tools, like optical satellites, see only the top of the canopy, leaving major uncertainties about what lies beneath.
Biomass’s unique P-band radar changes that. The long radio wavelength (~70 cm) enables the signal to travel through leaves and smaller branches, bouncing off larger woody elements. When these signals return to the satellite’s 12-meter deployable antenna, they carry detailed information about forest structure and weight — serving as a proxy for carbon storage.
This direct measurement technique is a significant leap forward from the patchy and indirect estimates scientists have relied on to date. It promises to reduce major uncertainties in carbon stock data, especially in remote and dense tropical forests where deforestation and degradation are accelerating.
Focus on Tropical Forests: Africa in the Spotlight
While Biomass is a global mission, its ability to penetrate dense vegetation makes it especially valuable for tropical regions — including Africa’s vast rainforests. These ecosystems are among the most carbon-rich and biodiversity-rich on the planet, yet they have been underrepresented in forest biomass datasets due to cloud cover and logistical challenges with ground measurements.
Scientists have already begun calibrating the satellite’s instruments using field data and aircraft surveys — particularly in Central African countries such as Gabon, where airborne radar missions are flying in tandem with Biomass observations to verify measurements.
Recent ESA graphics derived from the mission’s data show estimated carbon content — expressed as tonnes per hectare — across Congo Basin forests extending into Cameroon and the Central African Republic. These early visualizations are helping researchers better understand carbon distribution across landscapes that were previously data-poor.
Mission Deployment and Early Results
After launch, the satellite entered a sun-synchronous orbit roughly 660 km above Earth, circling the globe around 15-16 times daily. During the months following launch, ESA teams meticulously tested and calibrated the satellite’s systems in a commissioning phase to ensure it would deliver high-quality, reliable data.
By early 2026, ESA announced that Biomass was fully commissioned and that its data is now freely available to the global scientific community. This open-access policy aims to support international research and policymaking on forests and climate change, enabling scientists — including those in Africa — to use Biomass data for monitoring forest health, carbon fluxes, and changes over time.
The first public images and biomass maps from Biomass have already demonstrated its remarkable capabilities, with visuals revealing forest structure in areas long hidden from detailed observation. These early results represent only the beginning of a mission expected to run for at least five years.
A Boost for Climate Policy and Conservation
Reliable forest biomass data is more than a scientific milestone; it has profound implications for global climate policy. Accurate carbon stock measurements underpin international agreements, like the United Nations’ REDD+ mechanism, aimed at reducing emissions from deforestation and forest degradation.
By offering a consistent global picture of forest carbon, Biomass will help policymakers and conservation organizations make better-informed decisions — from targeting reforestation efforts to assessing the effectiveness of protected areas, and planning sustainable land-use strategies that balance development and environmental protection.
Moreover, the satellite’s capabilities go beyond forests. Its radar can also contribute to mapping subsurface geology in deserts, studying ice sheet structures, and improving digital terrain models under vegetation, broadening its scientific impact.
Looking Ahead
As Biomass continues to cycle Earth, researchers expect even richer datasets in the years ahead — including three-dimensional biomass maps and time-series analysis showing how forests change with climate pressures and human activities. With tropical forests at the heart of its mission, Africa stands to benefit from more accurate and timely insights into the condition of its critical ecosystems.
Source: Washington Post (Apr 29, 2025) — ESA’s Biomass satellite launches to map forest carbon - Africa in focus