Climate Science from Orbit

The Satellite Record Is the Climate Record — And It's Unambiguous

Satellite-based climate observations are not models or projections. They are direct measurements from instruments operating in orbit, calibrated against international standards, and continuously cross-validated against ground stations, ocean buoys, weather balloons, and ice cores over 50 years of continuous operation.

Consider what these instruments actually do. GRACE-FO — the Gravity Recovery and Climate Experiment Follow-On — measures Greenland's ice mass not by looking at it but by detecting minute changes in Earth's gravitational field as the spacecraft pair passes overhead. When Greenland loses ice, the gravitational pull in that region decreases measurably. GRACE-FO detects this. The result: Greenland is losing approximately 280 billion tons of ice per year, and Antarctica approximately 150 billion tons. These are not estimates from ice surface modeling. They are measured by weighing the ice sheets gravitationally from 490km altitude.

Sentinel-6 — launched in 2020 as the latest in the TOPEX/Poseidon/Jason series of radar altimeters — measures global mean sea level to approximately 1cm precision from an orbit of 1,336km. The current rate of rise is 3.6mm per year, and the rate itself is accelerating. The continuous altimetry record extends back to 1993 and shows a total rise of more than 100mm over that period. This record is not produced by a single satellite or a single agency — TOPEX was American-French, Jason series joint NASA-ESA-EUMETSAT-CNES, Sentinel-6 is ESA-NASA-EUMETSAT-NOAA. The continuity and multi-agency cross-validation makes this one of the most robust measurement records in Earth science.

OCO-2 — the Orbiting Carbon Observatory — maps atmospheric CO₂ concentrations globally at roughly 1km resolution. The 2024 annual mean is 424 parts per million, compared to a pre-industrial baseline of roughly 280ppm. Ice cores provide CO₂ records extending back 800,000 years. At no point in that record does CO₂ reach 300ppm. Current concentrations are the highest in at least 3 million years. OCO-2 also maps where carbon is being emitted and where it is being absorbed — revealing that tropical forests are absorbing less carbon than ground-based inventory models had assumed.

The satellite record has been continuously cross-validated by ground stations, buoys, and ice cores for 50 years. It is not a model. It is not a projection. It is a measurement archive. The question of whether this data is "enough to act on" is no longer a scientific question. The measurement problem is solved. What happens next is a policy question.

These are not news articles about climate data. These are the actual dashboards where satellite measurements are published in near-real-time. All free, all research-grade.