New Paper Asserts ‘Biased’ Climate Models Underestimate Natural Variability And The Warmth Of The Past

Climate Models Fail To Simulate

Past & Present NH Temperatures

Reconstructions Of Northern Hemisphere Temperatures Indicate Medieval Period Was As Warm As Recent Decades

Abrantes et al., 2017 

Otto and Roberts, 2016

Other NH Reconstructions Indicate Pre-Industrial Temps Were Highly Variable, 1940s As Warm As 2000s

Schneider et al., 2015

Stoffel et al., 2015

New Paper: Models Need ‘Forcing’ Adjustment…Underestimate Past Warmth, Internal Variability…Instrumental Record ‘Biased’

Büntgen et al., 2017

Spanning the period 1186-2014 CE, the new reconstruction reveals overall warmer conditions around 1200 and 1400, and again after ~1850. The coldest reconstructed summer in 1258 (-4.4°C wrt 1961-1990) followed the largest known volcanic eruption of the CE. The 20th century is characterized by pronounced summer cooling in the 1970s, subsequently rising temperatures until 2003, and a slowdown of warming afterwards. Little agreement is found with climate model simulations that consistently overestimate recent summer warming and underestimate pre-industrial temperature changes.

[W]hen it comes to disentangling natural variability from anthropogenically affected variability the vast majority of the instrumental record may be biased. … Although the causes of the recently measured slowdown in global and regional warming during the last decade are still debated (Karl et al. 2015; Fyfe et al. 2016), our study provides the first long-term proxy evidence for this temperature decline over the western Mediterranean basin. This finding is in line with local, regional and sub-continental meteorological observations, and consistent with the observations by Gleisner et al. (2015) that the post-2003 pause in rising mean surface temperatures is most strongly expressed at mid-latitudes.

The reconstructed long-term variability exceeds the pre-industrial multi-decadal to centennial variability in four state-of-the-art climate model simulations. This mismatch between the proxy reconstructions and the four model simulations is in line with a general tendency of state-of-the-art climate model simulations to underestimate the amplitude of reconstructed natural low-frequency temperature variability during the last millennium (Bothe et al. 2013; Fernández-Donado et al. 2013; Phipps et al. 2013; Luterbacher et al. 2016; Ljungqvist et al. 2012). Such disagreement might indicate that the role of internal unforced variability is greater than expected (Goosse 2017; Matsikaris et al. 2016), and/or that the climate sensitivity to the prescribed forcings needs adjustment. … [S]tate-of-the-art climate models are usually driven by a relatively dampened amplitude of long-term changes in solar activity (Schmidt et al. 2011,2012).

5 responses to “New Paper Asserts ‘Biased’ Climate Models Underestimate Natural Variability And The Warmth Of The Past”

  1. P Gosselin
  2. jako

    “Peer Review” is not sufficient deterrent for scientist to forge data/results for whatever objective. Perhaps a pillory for most and the rack for AGW proponents would make the difference…

  3. CO2isLife
  4. Paleoclimate | Pearltrees

    […] many NH regions were as warm or warmer than present during the “Medieval Climate Anomaly”.) New Paper Asserts ‘Biased’ Climate Models Underestimate Natural Variability And The Warmth Of Th…. By Kenneth Richard on 20. April 2017 Reconstructions Of Northern Hemisphere Temperatures Indicate […]

  5. New Paper Asserts ‘Biased’ Climate Models Underestimate Natural Variability And The Warmth Of The Past | Un hobby...

    […] Kenneth Richard, April 20, […]

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