CarbonBench: A Global Benchmark for Upscaling of Carbon Fluxes Using Zero-Shot Learning
This benchmark addresses the problem of accurately quantifying terrestrial carbon exchange for climate policy and carbon accounting by enabling systematic comparison of transfer learning methods, though it is incremental as it standardizes existing challenges rather than proposing new algorithms.
The authors tackled the lack of a standardized benchmark for evaluating zero-shot spatial transfer learning in carbon flux upscaling by introducing CarbonBench, which includes over 1.3 million daily observations from 567 global sites and provides stratified evaluation protocols to test generalization across unseen vegetation types and climate regimes.
Accurately quantifying terrestrial carbon exchange is essential for climate policy and carbon accounting, yet models must generalize to ecosystems underrepresented in sparse eddy covariance observations. Despite this challenge being a natural instance of zero-shot spatial transfer learning for time series regression, no standardized benchmark exists to rigorously evaluate model performance across geographically distinct locations with different climate regimes and vegetation types. We introduce CarbonBench, the first benchmark for zero-shot spatial transfer in carbon flux upscaling. CarbonBench comprises over 1.3 million daily observations from 567 flux tower sites globally (2000-2024). It provides: (1) stratified evaluation protocols that explicitly test generalization across unseen vegetation types and climate regimes, separating spatial transfer from temporal autocorrelation; (2) a harmonized set of remote sensing and meteorological features to enable flexible architecture design; and (3) baselines ranging from tree-based methods to domain-generalization architectures. By bridging machine learning methodologies and Earth system science, CarbonBench aims to enable systematic comparison of transfer learning methods, serves as a testbed for regression under distribution shift, and contributes to the next-generation climate modeling efforts.