Decreasing strength of Atlantic current may not be related to climate change

Nature : The Atlantic Meridional Overturning Circulation (AMOC) is part of the system of ocean currents that moves warm water from equatorial regions toward the poles. Since 2004, sensors in the Atlantic have recorded a decrease in the strength of the AMOC and the subsequent cooling of subtropical Atlantic waters. Scientists have speculated that climate change has contributed to the decline. Now Chris Roberts of the UK Met Office’s Hadley Centre and his colleagues have compared the recent trend with estimates of historical behavior from 14 climate–ocean models. They found that the decrease likely was within historical variations. The researchers say that the finding doesn’t rule out climate change’s influence but that 10 more years of data are likely necessary to be able to directly detect it. Regardless of the cause, the weakening of the current will likely have a significant influence on northwestern European climates.