In new research (Liu et al., 2026), scientists acknowledge clouds “markedly impact near-surface air temperatures” by altering the radiation budget and driving heating rates across the Arctic. For example, a cloudy day in winter may deliver 20-30 W/m² of cloud radiative forcing (CRF), warming the Arctic surface by 6-9°C.

However, due to massive uncertainties in estimating cloud fraction (CF) and their radiative effects, “substantial inconsistencies across datasets in trend magnitude” persist, and thus “there is still no consensus on the long-term trend of Arctic total CF over recent decades.”

Systematic errors (biases) in estimating downwelling shortwave (SW) can deviate by 90-160 W/m² from one dataset to the next. Overall, datasets disagree by 20-70 W/m² when estimating downwelling SW across the Arctic, and thus our measurements are “insufficient to meet the needs of radiation energy budget estimation.”

The increase in atmospheric CO2 is alleged to be the driver of modern Arctic warming. This attribution can be no more than speculation, however. The 20-70 W/m² uncertainty in estimating the Arctic’s surface solar radiation is 100 to 350 times larger than 10 years of accumulated clear-sky-only CO2 impacts (0.2 W/m² per Feldman et al., 2015).

Image Source: Liu et al., 2026