This is from a paper in Science last week, "Recent global temperature surge intensified by record-low planetary albedo," Goessling et al, Science 6-Dec-2024. [Link]
I can only make this chart so big, so expand it if you want a bigger picture. Same since Blogger insists on publishing fuzzy pictures (for me anyway).
Top graph A is surface temperature; the relevant graph as a cause is the bottom graph F, low cloud cover, and to a lesser extent total cloud cover E. The units for both E and F are percentages relative to 2001-2022 (viz., the entire interval).
Then in Table 1 (below) they give their numbers: among them, the planetary albedo (reflectance) has decreased by about -0.4% (negative change => smaller albedo => less reflectance of sunlight => warmer temperature). What's causing reduced lower cloud cover?
"Utilizing satellite and reanalysis data, we identify a record-low planetary albedo as the primary factor bridging this gap. The decline is apparently caused largely by a reduced low-cloud cover in the northern mid-latitudes and tropics, in continuation of a multi-annual trend. Further exploring the low-cloud trend and understanding how much of it is due to internal variability, reduced aerosol concentrations, or a possibly emerging low-cloud feedback will be crucial for assessing the current and expected future warming."
So if the planetary albedo was the canonical 0.30 (30% reflectance), it is now 0.2988. (Round that however you like.) Not much, but enough to matter.
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