"Switch" to North-westerly Flow noticeable from October 2007

A gradual shifting of the prevailing wind between October 2007 to present was noticeable in the North-West Atlantic close to the United Kingdom, which contributed to the wet and cool Summer of 2008 due to a strong (unstable) polar maritime flow. OnlineWeather.org.uk hedged bets that this "cut-off" to the usual tropical maritime flow into the UK, would produce below average temperature for northern-Europe during Winter 2008. The circulation effects are consistent with a warm temperature anomaly in the North Atlantic, but also indicate a longer-term shift in the climate system, which could result in a partial recovery or ease of Arctic ice melt. There is a strong signal that a warm temperature anomaly in the mid-Atlantic may have been present in 1981, when a long period of Arctic air resulted temperatures "well-below average" during December, and caused a "cool and wet summer", though reliable ocean data on a local scale is scarce during this period making this observation "inconclusive".

A significant weakening of the Gulf Stream flow would induce identical effects, and hence the Meriodional Overturning Circulation (MOC) plays a key role in dictating Global temperatures. Northern hemisphere ice cover during Winter and Spring, combined with high latitude ice coverage is consists a large negative feedback if MOC weakening is coincident with a warmer world. This Ocean-atmosphere coupling is essential in prediction of future climate change. There is evidence that the MOC has fluctuated in intensity naturally, though it is likely that the weakening seen is of a result of unprecedented ice-melt at the poles, well above the IPCC predictions. The MOC weakening is consistent with a global temperature leveling off during the early 21st century, when temperatures were otherwise (all thing equal) expected to accelerate in line with high levels of anthropogenic emissions.