The paper comes hot on the heels of another paper by England et al claiming that the 'pause' was due to an entirely different mechanism of strengthened Pacific trade winds, but which was readily debunked by skeptics and apparently not even believed by England himself anymore as he now claims
Drivers of decadal hiatus periods in the 20th and 21st Centuries
Nicola Maher, Alexander Sen Gupta, Matthew H. England
The latest generation of climate model simulations are used to investigate the occurrence of hiatus periods in global surface air temperature in the past and under two future warming scenarios. Hiatus periods are identified in three categories, (i) those due to volcanic eruptions, (ii) those associated with negative phases of the Interdecadal Pacific Oscillation (IPO) and (iii) those affected by anthropogenically released aerosols in the mid 20th Century. The likelihood of future hiatus periods is found to be sensitive to the rate of change of anthropogenic forcing. Under high rates of greenhouse gas emissions there is little chance of a hiatus decade occurring beyond 2030, even in the event of a large volcanic eruption. We further demonstrate that most non-volcanic hiatuses across CMIP5 models are associated with enhanced cooling in the equatorial Pacific linked to the transition to a negative IPO phase.
"We further demonstrate that most non-volcanic hiatuses across CMIP5 models are associated with enhanced cooling in the equatorial Pacific linked to the transition to a negative [Interdecadal Pacific Oscillation] IPO phase."The natural IPO is a close cousin of the ~60 year Pacific Decadal Oscillation, but with a cycle of 15–30 years, and affects both the North and South Pacific.
England et al boldly claims using the same climate models that did not predict the current pause of almost 18 years that after 2030, no more decadal 'pauses' of global warming will occur, stating,
Under high rates of greenhouse gas emissions there is little chance of a hiatus decade occurring beyond 2030, even in the event of a large volcanic eruption.
More circular reasoning from climate scientists that models which utterly failed to simulate the current 'pause' can be used to simulate the probability of a 'pause' in the future. Not to mention, CMIP model projections have already been falsified at confidence levels of 95-98+%.
As noted by Dr. Roy Spencer,
As noted by Dr. Roy Spencer,
"...they can’t ignore our arguments any longer. For many years we had been hearing from the “scientific consensus” side that natural climate change is nowhere near as strong as human-caused warming…yet the lack of surface warming in 17 years has forced those same scientists to now invoke natural climate change to supposedly cancel out the expected human-caused warming!
C’mon guys. You can’t have it both ways! They fail to see that a climate system capable of cancelling out warming with natural cooling is also capable of causing natural warming in the first place."
Drivers of decadal hiatus periods in the 20th and 21st Centuries
Nicola Maher, Alexander Sen Gupta, Matthew H. England
The latest generation of climate model simulations are used to investigate the occurrence of hiatus periods in global surface air temperature in the past and under two future warming scenarios. Hiatus periods are identified in three categories, (i) those due to volcanic eruptions, (ii) those associated with negative phases of the Interdecadal Pacific Oscillation (IPO) and (iii) those affected by anthropogenically released aerosols in the mid 20th Century. The likelihood of future hiatus periods is found to be sensitive to the rate of change of anthropogenic forcing. Under high rates of greenhouse gas emissions there is little chance of a hiatus decade occurring beyond 2030, even in the event of a large volcanic eruption. We further demonstrate that most non-volcanic hiatuses across CMIP5 models are associated with enhanced cooling in the equatorial Pacific linked to the transition to a negative IPO phase.
I'm glad Dr England has recognised the effect of the PDO.
ReplyDeleteNow he has found the PDO downswing explains the 'pause' perhaps he will determine how much the PDO upswing from 1970-2000 contributed to the rise in temperature during those years.
I'll help him out. Nearly 70%.
Which was therefore not due to CO2.
AGW fanatics only look at natural variability when it causes cooling, and ignore when it could have caused warming.
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