Saturday, May 08, 2021

Natural variability contributes to model–satellite differences in tropical tropospheric warming

Recommendable! How unreliable are climate models? Too much to have confidence in their predictions up to 100 years ahead!

It appears that these climate models do not represent well that e.g. oceans undergo multidecadal variability/cycles etc. What goes on in our oceans is still poorly understood, but it influences our climate significantly! I blogged e.g. here and here about multidecadal variability!

"Climate models have, on average, simulated substantially more tropical tropospheric warming than satellite data, with few simulations matching observations. It has been suggested that this discrepancy arises because climate models are overly sensitive to greenhouse gas increases. ...
It seems the newest generation of general circulation models, the Coupled Model Intercomparison Project Phase 6 (CMIP6), which are being used to generate the next set of reports from the Intergovernmental Panel on Climate Change, still haven’t resolved the discrepancy between model temperature projections and measured temperatures. Only 13 percent of the CMIP6 model realizations have tropical TMT trends within the observed trend range, the paper reports."

"... “A long-standing discrepancy exists between general circulation models (GCMs) and satellite observations: The multimodel mean temperature of the midtroposphere (TMT) in the tropics warms at approximately twice the rate of observations,” the authors write. ...
Our results indicate that multidecadal variability can explain current model–observational differences in the rate of tropical tropospheric warming. ...
Our results indicate that even on 40-y timescales, natural climate variability is important to consider when comparing observed and simulated tropospheric warming and is sufficiently large to explain TMT trend differences between models and satellite data."


Here is the link to the underlying research article:
Natural variability contributes to model–satellite differences in tropical tropospheric warming | PNAS


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