some things i think i know about the climate...rs b hd cu v i rss tropicallower tropospheric data...
TRANSCRIPT
Some ThingsI Think I KnowAbout the Climate
John R. ChristyUniversity of Alabama in Huntsville
Alabama State Climatologist
We at UAHuntsville build climate datasets from scratch to test assertions (hypotheses) being made about the climate system
"Global" Surface Temperature
Tmean is Average of Day and Night
HadCRUT3 (2011 Jan-May only)
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
1850 1870 1890 1910 1930 1950 1970 1990 2010
CO2 up 38% at current rate of 0.6% per year
East Africa TMax (Christy et al. 2009).
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
1900 1920 1940 1960 1980 2000
Obs: (HadCRUT3) +0.14 °C/decade
Kilimanjaro
East Africa TMax (Christy et al. 2009).
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
1900 1920 1940 1960 1980 2000
Obs: (UAH) +0.02 °C/decade
Obs: (HadCRUT3) +0.14 °C/decade
Kilimanjaro
CA Valley and Sierra Annual Avg TMax 1910-2003 .
18
20
22
24
26
28
1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
°C
Valley TMax
Sierra TMax
CA Valley and Sierra (Jun-Nov) 1910-2003
8
10
12
14
16
1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
°C
Valley TMin
Sierra TMin
Nighttime temperatures rising but not because of greenhouse gas warming, but nighttime readings are included in popular datasets
Daytime temperatures tell more accurate story
Christy 2002, Christy et al. 2006, 2007, 2009, Pielke et al 2008, Walters et al. 2007
Snyder et al. 2002
Sierras warm faster than Valley in model simulations
0.0
0.5
1.0
1.5
2.0
2.5
3.0
1875 1890 1905 1920 1935 1950 1965 1980 1995 2010
W Slope
9-Point avg
Western Slope Sierra Nevada Snowfall133 Years: 1878-79 to 2010-11
Average = 1.0
2010-11 Prelim
Fundamental issue is to discover how sensitive the climate system is to rising concentrations of CO2 and other
greenhouse gases
0.0 . 1.0 . 2.0 . 3.0 . 4.0 .
Zero FeedbackStefan-Boltzmann .
Warming for doubled CO2 °C .
Fundamental issue is to discover how sensitive the climate system is to rising concentrations of CO2 and other
greenhouse gases
0.0 . 1.0 . 2.0 . 3.0 . 4.0 .
Zero FeedbackStefan-Boltzmann .
Warming for doubled CO2 °C .
Model Projections(Positive feedback) .
Fundamental issue is to discover how sensitive the climate system is to rising concentrations of CO2 and other
greenhouse gases
0.0 . 1.0 . 2.0 . 3.0 . 4.0 .
Zero FeedbackStefan-Boltzmann .
Warming for doubled CO2 °C .
Model Projections(Positive feedback) .
Analysis(~zero to negative feedback) .
History Lesson 1988
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
1960 1970 1980 1990 2000 2010 2020
GISS-A(88)
GISS-B(88)
GISS-C(88)Predictions
History Lesson 1988
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
1960 1970 1980 1990 2000 2010 2020
GISS-A(88)
GISS-B(88)
GISS-C(88)
UAH-LT (SfcAdj)
RSS-LT (SfcAdj)
ObservationsJan-Jun 2011
Predictions
-0.05
0.00
0.05
0.10
0.15
0.20
0.25
0.30
1979 1985 1990 1995 2000
Median of Modeltrends
Mean of Model Trends
HadCRUT3v
UAHLTsfc
RSSLTsfc
Trends ending in 2011 with various start yearsIPCC AR4 Model Runs (22 models) vs. Obs.
Start Year
Vertical Temperature Change due to Greenhouse Forcing in Models
Model Simulations of Tropical Troposphere Warming:About 2X surfaceLee et al. 2007
Models: Mean and Standard Error
100
200
300
400
500
600
700
800
900
1000
-0.3 -0.2 -0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6
Model -2SEModel +2SEModel Best Guess
Best Estimate of Models - given surface trend close to observed
°C/decade
Observations: Four "corrected" Datasets
100
200
300
400
500
600
700
800
900
1000
-0.3 -0.2 -0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6
HadATIGRARATPACRICH
Upper air trends of four observed datasets are significantly cooler in this apples to apples comparison
°C/decade
Models vs. Obs
100
200
300
400
500
600
700
800
900
1000
-0.3 -0.2 -0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6
Model -2SEModel +2SEModel Best GuessHadATIGRARATPACRICH
Upper air trends of four observed datasets are significantly cooler in this apples to apples comparison (Douglass et al. 2007).
°C/decade
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
UAH5.4 LT
RSS3.3 LT
HadAT LT
RATPAC LT
RC1.4 LT
RICH LT
ERA-I
U-Air Mean
ERSST3b
HadCRUT3v
GISS LOI
RSS Tropical Lower Tropospheric data have spurious warming in the 1990s. Below is warming in RSS relative to
all other datasets (1996-7 minus 1991-1989)
Christy and Norris 2006, 2009; Christy et al. 2007, 2010, 2011; Klotzbach et al. 2008; Randal and Herman 2008.
0.0
0.5
1.0
1.5
2.0
0.0 0.1 0.2 0.3 0.4Trend K/decade
Models
UAH
RSS
HadATRATPAC
RAOBCORE
RICH
Ratio Trop/Tsfc Christy et al. 2010 .
Christy et al. 2010 .
Christy et al. 2007
Thorne et al. 2007 .
McKitrick et al. 2010
Over the interval 1979-2009, model-projected temperature trends are two to four times larger than observed trends in boththe lower and mid-troposphere and the differences are statistically significant at the 99% level. [Note: recalculated Santer et al. 2008 method, and even with surface trend variation found Santer et al.’s result is not verified.]
Klotzbach et al. 2010
[Our observational] result is inconsistent with model projectionswhich show that significant amplification of the modeled surfacetrends occurs in the modeled tropospheric trends.
Christy et al. 2010
Table 2 displays the new per decade linear trend calculations [of difference between global surface and troposphere using model amplification factor] … over land and ocean. All trends are significant at the 95% level.
Response of Clouds and Water Vapor (shortwave and longwave) to Increasing CO2
0
20
40
60
80
100
Relative Temperature Effect
Water Vapor and Clouds
CO2
Other
Negative Feedback?(mitigates CO2 impact)
Positive Feedback?(enhances CO2 impact - models)
0
1
2
3
4
5
6
7
8
0.00 0.10 0.20 0.30 0.40
Fraction of Record
Cu
m.
Av
era
ge
Re
gre
ss
ion
Slo
pe
(W
m-2
K-1
)
Terra CERES LW+SW vs UAH MT,
global (10 years)
CNRM CM3
CGCM31GFDL CM20
INM CM30ECHAM5
CSIRO MK30
The Real Climate System Behaves Very Differently from IPCC Climate Models
Less Sensitive
More Sensitive to forcing
Anaylses derived from Spencer and Braswell 2010 .
Spencer and Braswell 2011
Spencer and Braswell 2011Interannual climate sensitivity .
Time of Temperature Peak .
Net Radiative Flux .
Testing Hypothesis (assertions) about ClimateUAHuntsville builds datasets from scratch
1. Popular surface temperature datasets tend to be poor metrics for checking on the greenhouse effect - and they are often poorly measured as well
2. Warming is occurring but at a rate and in a manner that is inconsistent with model projections ofenhanced greenhouse warming
3. Sensitivity research suggests the climate is less sensitive to CO2 increases than depicted in models due to unaccounted-for negative cloud
feedbacks
Testing Hypothesis (assertions) about ClimateUAHuntsville builds datasets from scratch
1. Popular surface temperature datasets tend to be poor metrics for checking on the greenhouse effect - and they are often poorly measured as well
2. Warming is occurring but at a rate and in a manner that is inconsistent with model projections ofenhanced greenhouse warming
3. Sensitivity research suggests the climate is less sensitive to CO2 increases than depicted in models due to unaccounted-for negative cloud
feedbacks
Testing Hypothesis (assertions) about ClimateUAHuntsville builds datasets from scratch
1. Popular surface temperature datasets tend to be poor metrics for checking on the greenhouse effect - and they are often poorly measured as well
2. Warming is occurring but at a rate and in a manner that is inconsistent with model projections ofenhanced greenhouse warming
3. Sensitivity research suggests the climate is less sensitive to CO2 increases than depicted in models due to unaccounted-for negative cloud
feedbacks
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
199020002010202020302040205020602070208020902100
�C
P50 Mid-Range Scenario80% Reduction
50% Reduction
Net Impact if all US
adheres to 50%
reduction by 2050 is
0.07°C 2100
Scenario 50% and 80% reduction in US CO2 emissions by 2050 Climate Sensitivity of 1.5°C