At http://arstechnica.com/science/2013/01/the-clouds-are-alive-as-microbes-… … it all sounds a bit like the theory of Wickramasinghe and Hoyle a few years ago but it seems microbes have been found in clouds. The question is – what do they do? We are told they make them more reflective and inhibit precipitation. The paper is published this month in PNAS (DOI:10.1073/pnas.1205743110)
This paper is also in the same issue of PNAS – go to http://phys.org/print277450110.html … a team of scientists from Europe and Canada have put together a catalogue of cold blips over the last 1000 years in eastern Europe that they claim corresponds with social unrest and upheavel, even war and famine and the plague. The graph supplied still has a remarkable spike in temperatures during the late 20th century – so they are still at it by hiding the decline. Tree rings are not a reliable source for temperature as trees are influenced by other factors, such as crowding and space in the forest, or rainfall, snow, and droughts. In addition, the spike is created simply by switching from tree ring data to temperature thermometers and such like. Hence, the temperature goes up at the point the two are joined together. The tree ring data over the late 20th century do not show anything remarkable, which was an embarrassment to CAGW enthusiasts. Hence, the deliberate obfuscation of the real state of play. In this study they are using the graph for reasons unrelated to global warming or climate weirding but readers will notice the medieval warm period does not exist. However, tree rings do show periods when trees came under stress – presumably for environmental factors, and unusually low growth tree ring clusters cannot be explained by a year or so dry weather, but are more than likely associated with severe climatic downturns (cold causing the trees to remain dormant for a long period).