AI data centers shift 21.4 million tons of CO₂ abroad, study of 247 projects finds

The projects represent 37 gigawatts of planned load across 34 jurisdictions. Moving from low to high water stress cut siting probability by 5.7 percentage points, but the effect vanished where grids were low-carbon, which the authors read as firms putting carbon optics ahead of water risk. Three areas, central Arizona, northern Virginia and Madrid, carried 58% of the cross-border withdrawal burden.

The authors say 71% of the carbon leakage and 64% of the water leakage trace to firms covered by the EU Corporate Sustainability Due Diligence Directive. Yet 18% of those firms disclose project-level emissions and 7% report any water figure. Their estimates rest on announced design loads and average cooling coefficients, so realised impacts may differ.

The authors combined event-study and spatial-panel models with life-cycle assessment. They matched announced projects to hourly grid carbon factors and basin-level water-stress scores, then compared each project's footprint with running the same workload on the importing client's domestic grid. The carbon total is roughly the 2022 national inventory of Croatia.

The water finding is lopsided: Arizona, northern Virginia and Madrid carried 58% of the burden. The authors' model has 24/7 carbon-free power reducing carbon leakage from 21.4 to 11.6 Mt and hybrid cooling reducing water leakage from 1.78 to 1.12 billion litres. They argue the size and foreseeability of the harm meet the 'appreciable harm' standard in international law, a legal interpretation rather than a court finding.

The authors recommend hourly water reporting, a compute-adjusted border adjustment and a water footprint certificate, and say distributional effects fall on poorer communities.