by K. Richard, Mar 31, 2022 in NoTricksZone
Two weeks before Dr. Michael E. Mann and colleagues published their 23 April 1998 “hockey stick” chart in Nature, a peer-reviewed journal published a paper asserting “an overwhelming majority of climate scientists” (50 out of 60) view catastrophic human-caused global warming – and even global warming itself – as an “unsupported assumption”.
At the time, satellite data indicated the lower troposphere had cooled by 0.13°C between 1979 and 1994. The Arctic had cooled by -0.88°C since the 1940s.
It was thought the IPCC had just (1995) perpetrated a “disturbing corruption of the peer-review process” in manipulating the conclusions of scientists to support favored government policies.
by G. Müller-Plath, Nov 29, 2020 in WUWT
The present paper contributes a critical commentary on the recent finding by Mann, M. E., Steinman, B. A. and Miller, S. K (2020). Absence of internal multidecadal and interdecadal oscillations in climate model simulations. Nat. Commun. 11, 1–9.
Climate oscillations are recurring large-scale fluctuations in the surface temperatures of the oceans in connection with the atmosphere. This commentary focuses on the Pacific Decadal Oscillation (PDO, interdecadal timescale) and the Atlantic Multidecadal Oscillation (AMO, multidecadal timescale), which have been regarded as intrinsic climate drivers on the adjacent continents in numerous studies based on observations and paleoclimate reconstructions (Henley, 2017; O’Reilly et al., 2017). In a recent paper, Michael E. Mann and colleagues (Mann et al., 2020, hereafter M20) fail to find a PDO signal in global measured and modeled temperatures that is statistically different from noise. They further propose that the significant AMO-like signal is mainly due to anthropogenic aerosols in the 20th century, and to statistical artifacts before. Therefore they doubt the intrinsic nature of the two oscillations. The present paper shows that M20’s results are largely artifacts themselves with issues ranging from using inadequate data and referencing improper literature on anthropogenic aerosols with regards to the AMO to inappropriately interpreting the results with regards to the PDO.