by Javier, April 26, 2018 in WUWT
It is a well-known feature of climate change that since 1850 multiple climate datasets present a ~ 60-year oscillation. I recently wrote about it in the 7th chapter of my Nature Unbound series. This oscillation is present in the Atlantic Multidecadal Oscillation (AMO), Arctic Oscillation (AO), North Atlantic Oscillation (NAO), Pacific Decadal Oscillation (PDO), Length of Day (LOD), and Global (GST) and Northern Hemisphere (NHT) temperatures, with different lags.
To me this oscillation is not a cycle because prior to 1850 it had a more variable period and it is not well identified in LIA records. Since the origin of this oscillation is unknown, models have a hard time reproducing it and it is all but ignored by the IPCC. It is a big oscillation with an amplitude of ± 0.3 °C in NHT (0.1-0.2°C in GST; figure 2). While the long-term temperature trend is unaffected by it, there is a large effect on the 30-year trends. If this oscillation is considered, most of the climate alarmism vaporizes.