Today’s climate models are so inaccurate they must be improved a hundredfold just to detect a CO2 signal in climate change.

Though clouds “are the largest moderator of Earth’s radiation budget and their absorption of solar radiation directly influence our understanding of climate change,” NASA’s models of the cloud capacity to alter solar radiation diverge from satellite observations (MERRA2) by 18.8 W/m² (Fu et al., 2026).

“…the NASA MERRA2 modeled value [of the cloud capacity to absorb solar energy] is less than one-quarter of the observed.”

Image Source: Fu et al., 2026

To put this in perspective, the reported models-versus-observations discrepancy (18.8 W/m²) is 94 times larger than 10 years of accumulated clear-sky-only CO2 impacts (0.2 W/m² per Feldman et al., 2015).

NASA has previously admitted cloud impacts are so large and uncertain models “must be improved about a hundredfold in accuracy” to detect a human or CO2 impact on climate.

Image Source: NASA