Arctic Amplification and Extreme Weather
Francis, J.A. and Vavrus, S.J. 2012. Evidence linking Arctic amplification to extreme weather in mid-latitudes. Geophysical Research Letters 39: L06801 doi:10.1029/2012GL051000.
The paper seems to provide an evidential support of 'increasing' extreme weather events and its linkage to the AA-Arctic Amplification and, by extension, to the human-added CO2-induced warming of the Arctic region. However, it is important to note that several recent papers (e.g., Benestad, 2010; Lockwood et al., 2010) have linked low solar activity to cold winters in Europe. There are also other landmark papers by Namias (1955; 1982) on persistent droughts in the US mid-west and their possible linkage to colder SST ( Sea Surface Temperature) in the northeast pacific which could produce persistent blocking patterns leading to protracted heat waves and associated droughts in the US mid-west (e.g., 1980 heat wave, 1952-54 droughts). Thus, it may still be quite some time before the many factors influencing extreme weather events, including an anthropogenic influence (if any), are understood and properly accounted for.
Benestad, R. 2010. Low solar activity is blamed for winter chill over Europe. Environmental Research Letters 5: doi:10.1088/1748-9326/5/2/021001.
Lockwood, M., Harrison, R.G., Woollings, T. and Solanki, S.K. 2010. Are cold winters in Europe associated with low solar activity? Environmental Research Letters 5: doi:10.1088/1748-9326/5/2/024001.
Namias, J. 1955. Some meteorological aspects of droughts: with special reference to the summers of 1952-54 over the United States. Monthly Weather Review 83: 199-205.
Namias, J. 1982. Anatomy of Great Plains protracted heat waves (especially the 1980 US summer drought). Monthly Weather Review 110: 824-838 .