Scientists Probe Antarctic Ice to Settle Climate Debates
“The first samples already reveal intriguing evidence of climate complexity. In ice layers attributed to the Middle Ages, when Europe was unusually warm, the team found surprisingly high levels of carbon black particles, or soot. Levels were found to be twice as high as during the more heavily populated and industrialized 20th century, says geochemist Ross Edwards at the Desert Research Institute in Reno, Nev.
Overlooked in climate projections until recently, carbon black is a powerful warming agent. The soot, scientists speculate, came from giant wildfires that likely occurred in Australia and South America. So much soot could have raised temperatures.
Preliminary tests also showed that soot levels dropped during the cooler centuries after the Middle Ages, a period known as the Little Ice Age.”
More than soot on icesheets, there is soot on snow at lower latitudes changing albedo values. During Spring there can be high shortwave incoming with snow on the ground.
At Climate Etc today’s discussion was about a post by Nic Lewis about a recent PAGES 2k Consortium paper in Nature. I had a look at a plot below from a prior PAGES 2k study. I noticed a 5 dot V starting in about 1800 and ending in about 1900, followed by a trendline breakpoint. I speculated that the V showed synchronization as things started warming compared to the long term trend. Synchronization may occur followed by the climate jumping to another attractor. The new attractor may be warmer or cooler and it may either attempt to warm or cool the atmosphere. A theory accepted by some is that there is glacial and an interglacial attractor. If that is true, then shorter time scales could also have attractors. To understand attactors, look up Lorenz. Nic Lewis had discussed the low amount of forcing by CO2 in the 1830s. So I thought that with variable sensistivity (see Ghil) it could be possible that CO2 was detectible back then in a somewhat related way. Using the PAGES 2k plot below, the climate may have hit a lower threshold while the sensitivity value increased enough to cause some attractor jumps. I started looking for other indications of a 1800 to 1900 V shape in the climate measures.
And Then There’s Physics:
Contribution of solar and greenhouse gases forcing during the present warm period:
Other disciplines have moved away from gradualism as theory has shown that
such assumptions are unsustainable. However, climatology has been slow to respond, despite over fifty years having elapsed since the climate system was shown to be stochastic rather than deterministic over interannual to decadal timescales and perhaps longer (e.g., Ghil, 2012). A comprehensive theory of climate variability
remains to be developed (Ghil, 2012).