Based on the observations of heat content in the North Atlantic Ocean, the climate in the northern hemisphere is on the verge of a change that could last for several decades. This change is associated with the Atlantic Multidecadal Oscillation (AMO)[i] - a mode of natural variability occurring, with a period of 60 - 80 years, in the North Atlantic Ocean sea surface temperature (SST) field. The observed cooling does not apply just to the sea surface, but to the uppermost 700 metres of the ocean.
Observations made by Argo buoys have shown that the North Atlantic Ocean has been rapidly cooling since 2007. According to researchers Limin Zhoua, Brian Tinsley, Huimin Chua, Ziniu Xiaoc[ii] a significant correlation between the solar wind speed (SWS) and sea surface temperature (SST) in the region of the North Atlantic Ocean has been found during the Northern Hemisphere winters from 1963 to 2010. Suggested mechanisms for the solar influence on SST include: changes in atmospheric ionization and cloud microphysics affecting cloud cover; storm invigoration; and tropospheric dynamics. Such changes modify ‘upward wave propagation’ to the stratosphere, which in turn affects the dynamics of the polar vortex.
However, it may simply represent a natural recovery since the end of the previous cold period (the Little Ice Age).
If so, the general AMO increase since 1856 may well represent part of a longer natural variation. Also, direct solar inputs, including energetic particles and solar UV (ultra violet rays), produce dynamic changes in the stratosphere.
Image Featured at Top of Page:
Source: http://www.climate4you.com/ (oceans page)
Shows: North Atlantic (60-0W, 30-65N) heat content 0-700 m depth
[i] Source: http://www.cgd.ucar.edu/cas/catalog/climind/AMO.html
[ii] Source: http://www.sciencedirect.com/science/article/pii/S1364682616300360