Four Things I Think I Know About Climate - PowerPoint PPT Presentation

Loading...

PPT – Four Things I Think I Know About Climate PowerPoint presentation | free to download - id: 68f44e-NGZmO



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Four Things I Think I Know About Climate

Description:

I Think I Know About Climate John R. Christy University of Alabama in Huntsville Alabama State Climatologist – PowerPoint PPT presentation

Number of Views:9
Avg rating:3.0/5.0
Date added: 7 November 2019
Slides: 67
Provided by: JohnCh61
Learn more at: http://www.acs.org
Category:
Tags: climate | four | know | things | think

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Four Things I Think I Know About Climate


1
Four Things I Think I Know About Climate
  • John R. Christy
  • University of Alabama in Huntsville
  • Alabama State Climatologist

2
We should always begin our scientific assessments
with the following statement At our present
level of ignorance, we think we know
Paraphrase of Richard Mallory Hoover High
School Fresno CA Physics Teacher 1968
3
  • Testing Hypothesis (assertions) about Climate
  • UAHuntsville builds datasets from scratch
  • Popular surface temperature datasets are poor
    metrics for checking on the greenhouse effect -
    and they are poorly measured as well
  • Warming is occurring but at a rate and in a
    manner that is inconsistent with model
    projections of enhanced greenhouse warming
  • Sensitivity research suggests the climate system
    is less sensitive to CO2 increases as depicted in
    models due to unaccounted-for negative cloud
    feedbacks
  • 4. Impacts on global emissions of current
    legislative actions are minuscule and will have
    no discernable impact on whatever the climate is
    going to do

4
Testing Hypotheses on Global Warming 1. Testing
Assertions based on Popular Surface Temperature
Datasets Popular surface datasets tend to (a)
overstate the warming, and (b) serve as a poor
greenhouse metric
5
CO2 up 38 at current rate of 0.6 per year
6
Day vs. Night Surface Temp
Greenhouse signal
Warm air above inversion
Cold air near surface
Nighttime - disconnected shallow layer/inversion.
Temperature affected by land-use changes,
buildings, farming, etc.
Daytime - deep layer mixing, connected with
levels impacted by enhanced greenhouse effect
7
Night Surface Temp
Warm air above inversion
Warm air
Cold air near surface
Buildings, heat releasing surfaces, aerosols,
greenhouse gases, etc. can disrupt the delicate
inversion, mixing warm air downward - affecting
TMin.
Nighttime - disconnected shallow layer/inversion.
But this situation can be sensitive to small
changes such as roughness or heat sources.
8
MODIS 21 Jul 2002 Jacques Descloitres MODIS
Land Rapid Response Team NASA GSFC
9
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
10
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
11
1. (c) Some surface data sources are simply poor
12
Kilimanjaro
13
Kilimanjaro
14
  • Testing Hypothesis (assertions) about Climate
  • UAHuntsville builds datasets from scratch
  • Popular surface temperature datasets tend to be
    poor metrics for checking on the greenhouse
    effect - and they are often poorly measured as
    well
  • Warming is occurring but at a rate and in a
    manner that is inconsistent with model
    projections of enhanced greenhouse warming
  • Sensitivity research indicates the climate system
    is less sensitive to CO2 increases as depicted in
    models due to unaccounted-for negative cloud
    feedbacks
  • 4. Impacts on global emissions of current
    legislative actions are minuscule and will have
    no discernable impact on whatever the climate is
    going to do

15
Testing Hypotheses on Global Warming 2. (a)
Testing Assertions based on Climate Models for
global trend magnitude Climate models tend to
overstate or misrepresent the warming
16
Predictions
17
Predictions
Observations
18
G. Schmidt NASA/GISS
19
Individual Model Surface Trends 1979-2010
20
Trends ending in 2008 with various start
years IPCC AR4 Model Runs (22 models) vs. Obs.
Start Year
21
Trends ending in 2008 with various start
years IPCC AR4 Model Runs (22 models) vs. Obs.
Start Year
22
Trends ending in 2010 (Jun) with various start
years IPCC AR4 Model Runs (22 models) vs. Obs.
Start Year
23
Global Bulk Atmospheric Temperatures UAH
Satellite Data
Warming rate 50 of model projections Christy et
al. 2007, 2009
24
Testing Hypotheses on Global Warming Testing
Assertions based on Climate Models - Sierra
Nevada loses 80 of snow by 2100 Observations
contradict this
25
Sierras warm faster than Valley in model
simulations
Snyder et al. 2002
26
Trend 1.1 cm/decade
Christy and Hnilo 2010 .
27
Testing Hypotheses on Global Warming 2. (b)
Testing Assertions based on Climate Models
concerning Tropical Upper Air Temperature
trends Climate models tend to misrepresent the
observed relationship
28
A Climate Model Simulation is a Hypothesis How
does one define a falsifiable test for a model
hypothesis?
29
Douglass, Christy, Pearson and Singer
2007 Select a prominent metric dependent on the
main perturbation in forcing - a large signal -
test against observations One such signal is the
vertical structure of the tropical tropospheric
temperature trend - i.e. how surface and upper
air trends compare
30
Vertical Temperature Change due to Greenhouse
Forcing in Models
Model Simulations of Tropical Troposphere
Warming About 2X surface Lee et al. 2007
31
C/decade
Best Estimate of Models - given surface trend
close to observed
32
C/decade
Upper air trends of four observed datasets are
significantly cooler in this apples to apples
comparison
33
C/decade
Upper air trends of four observed datasets are
significantly cooler in this apples to apples
comparison (Douglass et al. 2007).
34
C/decade
Putting the hot and cold extremes (thick red) of
model trends tied to actual surface trend, models
are still too hot which in this case all models
have been tied to the actual observed surface
trend.
35
A different test asks whether the models and
observational upper air trends agree if NO
restriction is placed on the model surface trends
(i.e. apples to oranges.) Extremely weak
hypothesis to test and does NOT address the
sfc-to-upper air relationship (a key signature of
greenhouse warming in models.)
36
C/decade
Putting the hot and cold extremes (thick red) of
model trends tied to actual surface trend, models
are still too hot which in this case all models
have been tied to the actual observed surface
trend.
37
Ratio of Lower Tropospheric Trend to Surface
Trend (Amplification Ratio)
Model Median
Christy et al. 2007, 2010 Christy and Norris
2006, 2009 Randall and Herman 2008 Klotzbach et
al. 2009, 2010 McKitrick et al. 2010
38
Observations (Surface much more than upper air)
Land Surface Temperatures overstate warming
Model Expectation (Surface less than upper air)
39
Klotzbach 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.
Christy et al. 2010
Our result is inconsistent with model
projections which show that significant
amplification of the modeled surface trends
occurs in the modeled tropospheric trends.
McKitrick et al. 2010
Over the interval 1979-2009, model-projected
temperature trends are two to four times larger
than observed trends in both the 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.
40
  • Testing Hypothesis (assertions) about Climate
  • UAHuntsville builds datasets from scratch
  • Popular surface temperature datasets tend to be
    poor metrics for checking on the greenhouse
    effect - and they are often poorly measured as
    well
  • Warming is occurring but at a rate and in a
    manner that is inconsistent with model
    projections of enhanced greenhouse warming
  • Sensitivity research suggests the climate system
    is less sensitive to CO2 increases (as depicted
    in models) due to unaccounted-for negative cloud
    feedbacks
  • 4. Impacts on global emissions of current
    legislative actions are minuscule and will have
    no discernable impact on whatever the climate is
    going to do

41
Testing Hypotheses on Global Warming 3. Testing
Assertions on the sensitivity of the climate to
increases in greenhouse gas forcing Climate
models tend to overstate the sensitivity due to
missing negative cloud feedbacks
42
Response of Clouds and Water Vapor (shortwave and
longwave) to Increasing CO2
Negative Feedback? (mitigates CO2 impact)
Positive Feedback? (enhances CO2 impact - models)
43
A Climate Model Simulation is a Hypothesis How
does one define a falsifiable test for a model
hypothesis?
44
Select a prominent metric dependent on the main
perturbation in forcing - a large signal - test
against observations One such test is to
calculate the climate feedback parameter during
monthly and annual scale variations
45
Spencer and Braswell
46
Global Warming in Models is Greatly Magnified by
Positive Feedbacks
Warming in models amplified by clouds vapor (3
deg. C by 2100)
Warming from CO2 only
Satellite data suggests clouds reduce
warming (0.5C by 2100)
Spencer and Braswell .
47
  • Testing Hypothesis (assertions) about Climate
  • UAHuntsville 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 of enhanced 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
  • 4. Impacts on global emissions of current
    legislative actions are minuscule and will have
    no discernable impact on whatever the climate is
    going to do

48
Testing Hypotheses on Global Warming 4. Testing
Assertions the impact of regulations on
climate Regulations will have a minuscule impact
on whatever the climate is going to do
49
What did California do?
  • Force a limit on emissions of Light Duty Vehicles
  • California AB 1493 seeks to reduce tail-pipe
    emissions of CO2 by 26 by 2016
  • 11 NE States adopted AB 1493
  • Trial in Federal Court (Burlington VT) to address
    the engineering, legal and climate issues of AB
    1493, April-May 2007

50
What did California do?
  • Force a limit on emissions of Light Duty Vehicles
  • California AB 1493 seeks to reduce tail-pipe
    emissions of CO2 by 26 by 2016
  • 11 NE States adopted AB 1493
  • Trial in Federal Court (Burlington VT) to address
    the engineering, legal and climate issues of AB
    1493, April-May 2007

51
What did California do?
  • Force a limit on emissions of Light Duty Vehicles
  • California AB 1493 seeks to reduce tail-pipe
    emissions of CO2 by 26 by 2016
  • 11 NE States adopted AB 1493
  • Trial in Federal Court (Burlington VT) to address
    the engineering, legal and climate issues of AB
    1493, April-May 2007

52
What did California do?
  • Force a limit on emissions of Light Duty Vehicles
  • California AB 1493 seeks to reduce tail-pipe
    emissions of CO2 by 26 by 2016
  • 11 NE States adopted AB 1493
  • Trial in Federal Court (Burlington VT) to address
    the engineering, legal and climate issues of AB
    1493, April-May 2007

53
IPCC Best Estimate
54
California AB 1493 26 CO2 reduction LDV 2016
55
The temperature impact on global temperatures if
the entire world adopted AB 1493 is an
undetectable 0.03C. Latest sensitivity results
suggest the impact is even smaller.
56
Judge William Sessions III Ruling 12 Sept
2007 AB 1493 is legal
Pg 46 Plaintiffs expert Dr. Christy estimated
that implementing the regulations across the
entire United States would reduce global
temperature by about 1/100th (.01) of a degree by
2100. Hansen did not contradict that testimony.
57
Questions
  • What could make a dent in forecasted global
    temperatures?
  • What would be the impact of building 1000 nuclear
    power plants and putting them on-line by 2020?
  • (average 1.4 gigawatt output each)

58
Questions
  • What could make a dent in forecasted global
    temperatures?
  • What would be the impact of building 1000 nuclear
    power plants and putting them on-line by 2020?
  • (average 1.4 gigawatt output each)

59
IPCC Best Estimate
60
Net Effect of 10 CO2 emission reduction to A1B
Scenario (1000 Nuclear Plants by 2020)
61
  • Testing Hypothesis (assertions) about Climate
  • UAHuntsville builds datasets from scratch
  • Popular surface temperature datasets tend to be
    poor metrics for checking on the greenhouse
    effect - and they are often poorly measured as
    well
  • Warming is occurring but at a rate and in a
    manner that is inconsistent with model
    projections of enhanced greenhouse warming
  • Sensitivity research suggests the climate is less
    sensitive to CO2 increases than depicted in
    models due to unaccounted-for negative cloud
    feedbacks
  • 4. Impacts on global emissions of current
    legislative actions are minuscule and will have
    no discernable impact on whatever the climate is
    going to do

62
Kenya, East Africa
63
Energy System
Energy Source
Energy Transmission
Energy Use
64
Consensus is not Science
Michael Crichton
65
Consensus is not Science
Michael Crichton
All Science is numbers
William Thomson (Lord Kelvin)
66
(No Transcript)
About PowerShow.com