Satellites can now see methane at two very different scales. Instruments like TROPOMI map the whole planet every day but average emissions over tens of kilometres. Instruments like GHGSat, EnMAP, PRISMA, EMIT and Tanager can pick out an individual leaking facility, but only glimpse it for a moment. Neither alone tells a country what its emissions are.
SMART-CH4 spent its first phase making both kinds of data better — and finding out exactly where they still break. Two things break hardest. Point-source detections cannot yet be added up into regional or national budgets. And the models used to interpret satellite data carry a systematic bias in the stratosphere large enough to distort the emissions they infer at the surface.
Those two failures are what Phase 2 exists to fix.
Four improvements now in the operational TROPOMI CH4 product, plus TROPOMI/WFMD v2.0 and the EMMA v5.1 merged multi-sensor record.
A better methane cross-section table widens the usable thermal-infrared window — and takes the first step toward isotopes from orbit.
217 persistent methane source regions, machine-learning plume quantification, and the Bucharest landfill that emits 40× its official figure.
Europe, Romania, Scandinavia and the Tropics — and a warning about how much the choice of retrieval product still matters.
The finding that created Phase 2: global models get the stratosphere wrong, and that error leaks into surface emission estimates.
A new global δ13C-CH4 source-signature dataset, and a clear-eyed assessment of what it would take to detect it from space.