The Pause The Thing John W NielsenGammon Regents Professor of Atmospheric Sciences Texas AampM University Texas State Climatologist Sen Cruz vs Mair Oct 8 2015 https youtube ID: 480379
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Slide1
The Hiatus
The PauseThe Thing
John W. Nielsen-Gammon
Regents Professor of Atmospheric Sciences, Texas A&M University
Texas State ClimatologistSlide2
Sen. Cruz vs. Mair, Oct. 8, 2015
https://youtu.be/Sl9-tY1oZNw[5:17 – 6:32]Slide3
IPCC AR5 WG1 Explanation of The Thing
Natural variability does this sort of thingRadiative forcing was weakerSome models overestimate climate sensitivityConfidence levels:Medium for explanationsLow for numbersNot discussed: was warming undersampled by observations? [1] [2] [3]Slide4Slide5Slide6Slide7Slide8
Trends: 0.08 °C/decade to 0.12 °C/decadeSlide9
Trends: -0.01 °C/decade, -0.03 °C/decade, 0.08
°C/decade Slide10
Trends: 0.09 °C/decade, 0.07 °C/decadeSlide11
Total Solar IrradianceSlide12
Total Solar IrradianceSlide13
Total Solar IrradianceSlide14
Natural Variability as an Explanation, not an Excuse
What natural variations produced a slowdown in warming, and how?Did oceans continue uptake of energy, and how?What does this mean for climate predictions/projections?Slide15
ENSO/PDO/IPO: Fun in the Pacific
Model with observed East Pacific SST simulates the Thing [1]Slide16
ENSO/PDO/IPO: Fun in the Pacific
Model with observed East Pacific SST simulates the Thing [4]Same thing happens with observed enhanced trade winds [5]Modeled global temperature can be overly sensitive to tropical Pacific SST [6]Statistical allocation 2002-2011 [7] (also [8]):+0.19 °C anthro, -0.11 °C Pacific, -0.04 °C solarSlide17Slide18
Subsurface Ocean Warming
Top 100 m cooled; 100-300 m layer warmed [9]Slide19
Subsurface Ocean Warming
Top 100 m cooled; 100-300 m layer warmed [9]Warm water in West Pacific flows to Indian Ocean [10]Slide20
The Thing is Predictable
Spin up model with observed winds, and decadal variability can be forecasted [11]Slide21
Short-range climate forecasts
IPCC AR5 WG1 Fig. 11.9bSlide22
Short-range climate verification
IPCC AR5 WG1 Fig. 11.9b, updatedSlide23
IPCC AR5 WG1 Fig. 11.25aSlide24
IPCC AR5 WG1 Fig. 11.25a, updatedSlide25
IPCC Model & Expert Judgment
IPCC AR5 WG1 Fig. 11.25bSlide26
IPCC Model & Expert Judgment
IPCC AR5 WG1 Fig. 11.25b, updatedSlide27
Causes of the Thing
Natural variability, mainly Pacific Ocean (likely, major)Reduced radiative forcing (solar + ?) (very likely, minor)Observational issues (likely, very minor)Are models overly sensitive? Quite possibly, but not because of The ThingSlide28
Contact Information
John W. Nielsen-GammonN-g@tamu.eduhttp://climatexas.tamu.eduhttp://climatechangenationalforum.orgSlide29
References
[1] Cowtan and Way, 2014, Quarterly Journal RMS[2] Saffioti et al., 2015, Geophysical Research Letters[3] Karl et al., 2015, Science[4] Kosaka and Xie, 2013, Nature[5] England et al., 2014, Nature Climate Change[6] Douville et al., 2015, Geophysical Research Letters[7] Johansson et al., 2015,
Nature Climate Change
[8] Dai et al., 2015,
Nature Climate Change
[9] Nieves et al., 2015, Science
[10] Lee et al., 2015, Nature Geoscience
[11]
Thoma
et al., 2015,
Geophysical Research LettersSlide30
Bonus SlidesSlide31Slide32Slide33
[7]Slide34
[7]