claim: When stomata-derived CO2 (red) is compared to ice core-derived CO2 (blue), the stomata generally show much more variability in the atmospheric CO2 level and often show levels much higher than the ice cores.
evidence: According to a study published in 2016, about 0.5 °C (0.90 °F) of the warming in the Arctic has been attributed to reductions in sulfate aerosols in Europe since 1980.