A pertinent climate question
Posted on March 28, 2021 by curryja | 56 Comments
by Michel de Rougemont
Not so innocent as it looks, a pertinent question is asked by Judith Curry on Twitter:
How much of a change in cloudiness would it take to account for the 0.53 W/m2 increase in TOA radiative forcing since 2003?
https://twitter.com/curryja/status/1375144537522204672She asks it in relation with a recent article accepted for publication on Observational evidence of increasing global radiative forcing (Kramer et al., 2021).
Abstract. “Changes in atmospheric composition, such as increasing greenhouse gases, cause an initial radiative imbalance to the climate system, quantified as the instantaneous radiative forcing. This fundamental metric has not been directly observed globally and previous estimates have come from models. In part, this is because current spaceâ€based instruments cannot distinguish the instantaneous radiative forcing from the climate’s radiative response. We apply radiative kernels to satellite observations to disentangle these components and find allâ€sky instantaneous radiative forcing has increased 0.53±0.11 W/m2 from 2003 through 2018, accounting for positive trends in the total planetary radiative imbalance. This increase has been due to a combination of rising concentrations of wellâ€mixed greenhouse gases and recent reductions in aerosol emissions. These results highlight distinct fingerprints of anthropogenic activity in Earth’s changing energy budget, which we find observations can detect within 4 years.â€
https://judithcurry.com/2021/03/28/a-pertinent-climate-question/#more-27365
