Anyone see this fascinating abstract in Nature

[Drz1111]

"Aerosols implicated as a prime driver of twentieth-century North Atlantic climate variability"

Systematic climate shifts have been linked to multidecadal variability in observed sea surface temperatures in the North Atlantic Ocean¹. These links are extensive, influencing a range of climate processes such as hurricane activity² and African Sahel^{3, 4, 5} and Amazonian⁵ droughts. The variability is distinct from historical global-mean temperature changes and is commonly attributed to natural ocean oscillations^{6, 7, 8, 9, 10}. A number of studies have provided evidence that aerosols can influence long-term changes in sea surface temperatures^{11, 12}, but climate models have so far failed to reproduce these interactions^{6, 9} and the role of aerosols in decadal variability remains unclear. Here we use a state-of-the-art Earth system climate model to show that aerosol emissions and periods of volcanic activity explain 76 per cent of the simulated multidecadal variance in detrended 1860–2005 North Atlantic sea surface temperatures. After 1950, simulated variability is within observational estimates; our estimates for 1910–1940 capture twice the warming of previous generation models but do not explain the entire observed trend. Other processes, such as ocean circulation, may also have contributed to variability in the early twentieth century. Mechanistically, we find that inclusion of aerosol–cloud microphysical effects, which were included in few previous multimodel ensembles, dominates the magnitude (80 per cent) and the spatial pattern of the total surface aerosol forcing in the North Atlantic. Our findings suggest that anthropogenic aerosol emissions influenced a range of societally important historical climate events such as peaks in hurricane activity and Sahel drought. Decadal-scale model predictions of regional Atlantic climate will probably be improved by incorporating aerosol–cloud microphysical interactions and estimates of future concentrations of aerosols, emissions of which are directly addressable by policy actions.

[donsutherland1]

The paper's conclusion:

We have shown that volcanic and aerosol processes can drive pronounced multidecadal variability in historical NASST, which leads to improved (for the early twentieth century) or reproduces (for the later period) the observed historical trends. In these simulations, it is the inclusion of aerosol indirect effects that allows us to capture the magnitude and the temporal and spatial structure of SST variability. Our results show that volcanoes and, crucially (from a policy and climate impact perspective), anthropogenic emissions of aerosols can drive NASST variability resembling that which is observed. This work suggests that we need to reassess the current attribution to natural ocean variability of a number of prominent past climate impacts linked to NASSTs, such as Sahel drought.

NASST = North Atlantic sea surface temperature

A major implication of the paper's conclusion is that there may be an anthropogenic link to North Atlantic SSTs. If so, the anthropogenic impact may extend beyond long-term climate to cyclical variability associated with North Atlantic SSTAs.