One characteristic of our changing climate is that while the Earth is heating up slowly, both the frequency and wildness of our extreme weather is increasing, noted Fred Heutte of the Sierra Club recently. For example, look at ENSO, the El Nino Southern Oscillation, the most important global short-term climate driver, which teleconnects to affect many climate systems. ENSO operates like a giant water-and-air piston, moving through its cycle within a decade. The up and down positions of this piston correspond to two coupled weather systems, El Nino and La Nina. ENSO has been very active in the last several years. A moderate El Nino was followed swiftly by a pretty big La Nina, which had tremendous consequences globally — record droughts and heat in Texas and Moscow, and record deluges in Pakistan, among many other outcomes.
Well, fasten your seat belts, folks. The National Oceanic and Atmospheric Administration has announced that we appear to be heading immediately back into an even bigger La Nina. Is global warming intensifying ENSO? Possibly. But what we KNOW is that climate models predict more extreme weather under global warming. And that global warming occurs in combination with other planetary processes — such as ENSO — to produce climate change.
Update: Since this was written (about a week ago), an unusually early snow storm has hit the Northeast US. http://edition.cnn.com/2011/10/29/us/east-coast-storm/?hpt=us_c1
Fred Heutte is Chair of the Global Warming and Clean Energy Committee, Sierra Club. The first part of this text, unlike most other CCRs, is derived from an email communication he recently distributed to interested parties. I particularly like his apt piston analogy to the ENSO. The NOAA link on the upcoming La Nina is: http://www.noaanews.noaa.gov/stories2011/20111020_winteroutlook.html
Just a little wiki on ENSO in the US: the Pacific Ocean is a giant heat reservoir that drives global wind patterns. During El Nino, the east Pacific warms, and the northern US winters tend to be warmer, drier, while the southern US winters tend to be wetter. During La Nina, the east Pacific cools, with the opposite effects of El Nino.