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That's a nice story you tell about talking to a Professor. https://www.nature.com/articles/d41586-019-01791-6 How much have aerosol particles slowed warming? Joyce Penner sets out priorities for a coordinated campaign of observations and modelling. https://media.nature.com/lw800/magazine-assets/d41586-019-01791-6/d41586-019-01791-6_16780224.jpg so take a look at the image It shows a half a degree Celsius in uncertainty in the models. So the author is citing the IPCC report that you rely on. Now look at this:
We need to rethink everything we know about global warming
New calculations show scientists have grossly underestimated the effects of air pollution https://www.sciencedaily.com/releases/2019/01/190122104611.htm
So the Gee McFearSun reasons with this:
"The cooling effect is “nearly twice what scientists previously thought.” That this February 2019 paper cites the conclusion by Levy et al. (2013) https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/jgrd.50192 indicating as little as 35% reduction in industrial activity drives a 1 C global-average rise in temperature suggests that as little as a 20% reduction in industrial activity is sufficient to warm the planet 1 C within a few days or weeks."
So now we click on the link source cited
"we find that the dramatic emission reductions (35%–80%) in anthropogenic aerosols and their precursors projected by Representative Concentration Pathway (RCP) 4.5 result in ~1 °C of additional warming"
So what is misleading - something that GEE McFearSun missed - is that the 35% to 80% is not just a range but a qualitative difference:
"By 2100, RCP4.5 projects an 80% reduction in SO2 emissions, a 50% reduction in BC emissions, and a 35% reduction in OC emissions [Lamarque et al., 2011]."
And so ...So we could say then due to the doubling of the estimates then a 40% global decrease of sulfates from coal and oil equals 1 degree Celsius:
"On the other hand, the aerosols have a cooling (“masking”) effect of about −0.9 °C."
OK so now we go the top science journal Nature - and what do we find?
"It has already been suggested by previous authors8,9, and supported by our results, that some of the earlier satellite-based estimates of RFaci, used in IPCC-AR5, were biased low due to the use of AOD as CCN proxy. We find that also the AI estimates are biased low by almost 50% due to issues at low-AI values. Our RFaci estimate overcomes the known issues with previous estimates by using aerosol measurements more directly related to aerosol–cloud interactions (aerosol number, size, and shape)14,15 and by using only measurements in the range not dominated by measurement uncertainties. The lower bound of our range (RFaci = −0.84 W m−2) is almost a factor 2 more negative than the IPCC-AR5 estimate of ERFaci, and is actually more in line with the IPCC-AR4 estimate. Our best estimate of RFaci = −1.14 W m−2 is even more negative than the IPCC-AR5 estimate of −0.90 W m−2 for the total aerosol radiative forcing (ERFaci+ari). These findings put into question that by expert judgement the satellite studies were given more weight than model estimates in IPCC-AR5, resulting in a weaker negative forcing than IPCC-AR4, in particular because our estimate is more in line with the models and with IPCC-AR4. A stronger aerosol cooling indicates that the global temperature is more sensitive to anthropogenic greenhouse gas emissions than previously assumed31, because it partly masks the warming by greenhouse gases32."
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