Climate Monitoring from Space: How Satellites Track Global Change

The global climate system operates across spatial scales from individual storm cells to ocean basins thousands of kilometers wide, and across time scales from daily weather patterns to centuries-long glacial cycles. Only satellites can observe this system with the spatial coverage, measurement consistency, and repeat frequency that quantitative climate science demands. Over the past five decades, the archive of satellite Earth observation data has become one of the most scientifically valuable datasets humanity has ever assembled.

What Satellites Measure

Modern Earth observation satellites carry a wide range of sensors, each designed to measure specific components of the climate system:

• Sea surface temperature (SST): Measured by thermal infrared sensors on platforms including NOAA's GOES series, the AVHRR instrument series, and ESA's Sentinel-3. Consistent SST records from the early 1980s onward document warming trends in the world's oceans with high spatial detail.
• Sea level and ocean altimetry: The TOPEX/Poseidon mission, followed by Jason-1, -2, -3, and now Sentinel-6 Michael Freilich, have measured global mean sea level continuously since 1992 with centimeter-level accuracy. The satellite altimetry record shows a mean sea level rise trend well-documented in the peer-reviewed literature.
• Ice sheet and glacier mass balance: NASA's GRACE (Gravity Recovery and Climate Experiment) and its successor GRACE-FO measure tiny changes in Earth's gravity field caused by redistribution of mass, including the loss of ice from Greenland and Antarctica. ICESat-2 uses laser altimetry to measure ice surface elevation changes with unprecedented precision.
• Atmospheric composition: The Orbiting Carbon Observatory-2 (OCO-2) and OCO-3 measure column CO₂ concentrations globally. ESA's Sentinel-5P carries the TROPOMI instrument, which maps methane, nitrogen dioxide, ozone, and other trace gases with high spatial resolution, enabling detection of individual emission sources including oil and gas facilities and landfills.
• Land surface changes: The Landsat series, now in its 50th year, provides the longest continuous record of land surface change from space, documenting deforestation, urban expansion, agricultural shifts, and wetland loss. Sentinel-2 complements Landsat with higher revisit frequency.
• Vegetation and biomass: MODIS and VIIRS instruments measure vegetation indices (NDVI, EVI) that track ecosystem health, drought stress, and agricultural productivity at global scale.
• Cloud cover and radiation budget: The CERES (Clouds and the Earth's Radiant Energy System) instruments measure Earth's energy budget (the balance between incoming solar radiation and outgoing infrared), which is the fundamental quantity governing global temperature.

The Challenge of Long-Term Climate Records

Scientific-quality climate monitoring requires more than just launching instruments. It requires:

• Calibration and stability: Sensors degrade in the space environment, and small calibration drifts can masquerade as climate signals. Intercalibration between overlapping satellite missions is essential for producing consistent multi-decade records.
• Ground truth: Satellite retrievals must be validated against in-situ measurements: Argo floats for ocean temperature, weather balloons for atmospheric profiles, GPS ground stations for ice sheet kinematics.
• Data continuity: A gap in satellite coverage can permanently degrade a climate record. Maintaining overlap between successive missions, ensuring one satellite is operational before its predecessor fails, is a mission planning priority for operational agencies.

Commercial Earth Observation and Climate Applications

Commercial satellite operators are increasingly contributing to climate monitoring. Planet's fleet of PlanetScope and SkySat satellites enables daily global coverage at meter-scale resolution, supporting deforestation monitoring, permafrost mapping, and agricultural drought assessment at spatial scales previously impossible with government satellites.

Dedicated greenhouse gas monitoring companies including GHGSat (now part of Viasat) and Satellogic are commercializing the capability to attribute methane emissions to specific industrial facilities, a capability that has significant implications for both environmental compliance and carbon markets.

Policy Implications and Commercial Opportunities

As climate disclosure regulations expand (including mandatory scope 3 emissions reporting requirements emerging across multiple jurisdictions), satellite data is increasingly being used to independently verify corporate emissions claims and supply chain impacts. This creates a growing commercial market for Earth observation analytics services that intersect climate science and financial due diligence.

Space agencies including NASA, ESA, JAXA, and ISRO coordinate climate monitoring missions through the Committee on Earth Observation Satellites (CEOS), ensuring that the global observation system covers key variables across multiple sensors and providers.

Explore Earth observation satellite capabilities and coverage on the SpaceNexus satellite tracker, and track market developments in the commercial Earth observation sector through our market intelligence module.