Climate Change By the Numbers: Climate Change By the Numbers John R. Christy
University of Alabama in Huntsville
Alabama State Climatologist
Slide2: Consensus is not Science Michael Crichton
Slide3: Consensus is not Science William Thompson (Lord Kelvin) All Science is numbers Michael Crichton
Slide4: Some people will do anything to save the Earth ...
Slide5: Some people will do anything to save the Earth ... except take a science course. Greenhouse “Affect”, Rolling Stone
P.J. O’Rourke
The Basic Numbers: The Basic Numbers Carbon Dioxide has increased 35%
Global Surface temperature rose 0.7 °C in past 100 years
Surface temperature response to 2xCO2 increases (alone) is ~ 1 C
The associated feedbacks are where the uncertainties are large (i.e. no confident numbers)
The Basic Numbers: The Basic Numbers Humans produce about 7 to 8 gigatons of CO2 (carbon mass) per year mainly from energy production
About 3.5 to 4 gigatons accumulate in the air each year
There are about 740 gigatons of CO2 in the atmosphere
CO2 in the atmosphere is increasing around 0.5% per year
The Basics: The Basics Climate is always “changing”
Global temperature is rising or falling
Sea level is rising or falling
Glaciers are retreating or advancing
Slide9: Mean Surface Temperatures A Proper Metric?
Slide10: Modelers knew the answer ahead of time - not a true scientific experiment. The scientific method requires an independent comparison - i.e. upper air temperatures which modelers in general did not force agreement. IPCC SPM
Is Mean Surface Temperature an Appropriate Index for the Greenhouse Effect?: Is Mean Surface Temperature an Appropriate Index for the Greenhouse Effect? TMean = (TMax + TMin)/2
TMean = (Daytime + Nighttime)/2
Day vs. Night Surface Temp: Day vs. Night Surface Temp 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
Night Surface Temp: Night Surface Temp Nighttime - disconnected
shallow layer/inversion. But this situation can be sensitive to small changes such as roughness or heat sources. Buildings, heat releasing surfaces, aerosols, greenhouse gases, etc. can disrupt the delicate inversion, mixing warm air downward - affecting TMin. Warm air above inversion Cold air near surface Warm air
No. Alabama Summer TMax Temperatures 1893-2007: No. Alabama Summer TMax Temperatures 1893-2007 Christy 2002, updated to 2007
Alabama Annual Precipitation 1896-2007: Alabama Annual Precipitation 1896-2007
Annual Mean Temperature: Annual Mean Temperature
Mean Surface Temperature Southeast USA 1899-2003: Mean Surface Temperature Southeast USA 1899-2003 Models Observation
Slide18: Christy et al. 2006, J. Climate
Slide19: MODIS
21 Jul 2002
Jacques Descloitres
MODIS
Land Rapid Response Team
NASA GSFC
Slide20: Snyder et al. 2002 Sierras warm faster than Valley in model simulations
Slide21: Christy et al. 2006
Slide22: Main Point:
Average surface temperatures (average of daytime and nighttime) are poor proxies for greenhouse detection because of nighttime contamination by human development - likely overstating actual atmospheric warming. Models do not replicate past regional temperature well in many places, including the Southeast.
Christy 2002
Christy et al. 2006
Pielke, Sr. 2007
Walters et al. 2007
Upper Air Temperatures A Better Proxy: Upper Air Temperatures A Better Proxy
Vertical Temperature Change due to Greenhouse Forcing in Models: Vertical Temperature Change due to Greenhouse Forcing in Models Model Simulations of Tropical Troposphere Warming:
About 2X surface
Lee et al. 2007
Upper Air Tropical Trends: Upper Air Tropical Trends Christy and Norris 2006,
Christy et al. 2007
Douglass et al. 2007
Slide26: Global Bulk Atmospheric Temperatures
UAH Satellite Data Warming rate 60% of model projections
Slide27: Main Point:
Better proxies (daytime surface temperature and tropospheric temperatures) show only modest changes, and no change in the Southeast, neither of which are reproduced well in models. • Christy and Spencer 2005
• Christy and Norris 2006
• Christy et al. 2007
Slide28: Greenhouse Effect
Total Greenhouse Effect: Total Greenhouse Effect Water vapor and Clouds Dominate
Total Greenhouse Effect is variable
Climate models show strong water-vapor/cloud positive feedback with increased CO2
Greenhouse Effect: Greenhouse Effect
Greenhouse Response of Clouds and Water Vapor to Increasing CO2: Greenhouse Response of Clouds and Water Vapor to Increasing CO2 Negative Feedback?
(mitigates CO2 impact) Positive Feedback?
(enhances CO2 impact - models)
Tropical Temp. and Cloud Forcing on month-to-month time scales Negative feedback [Spencer et al. (2007)] Cloud variations act to counter temperature rises (Heat trapping clouds decrease when air is warmed): Tropical Temp. and Cloud Forcing on month-to-month time scales Negative feedback [Spencer et al. (2007)] Cloud variations act to counter temperature rises (Heat trapping clouds decrease when air is warmed) Cloud Response
Slide34: • • 2007: Jan-Aug only
Slide35: Main Point:
The most important greenhouse components (clouds and water vapor) are poorly understood and poorly characterized in climate models
Spencer et al. 2007
“Models tend to overestimate positive feedback from water vapor …[and] underestimate negative feedback from cloud[s]” Sun et al. 2007.
“The low equilibrium climate sensitivity … [is] well below current best estimates ... in the IPCC (2007)” Schwartz 2007.
Slide36: Cold Places?
Slide37: Arctic Sea Ice Chapman, U.Illinois
North Polar Regions Temperature HadCRUT3: North Polar Regions Temperature HadCRUT3 Satellite Sea Ice Record
Greenland Summer Temperatures Vinther et al. 2005: Greenland Summer Temperatures Vinther et al. 2005
Greenland Borehole Temperature Dahl-Jensen et al. 1998: Greenland Borehole Temperature Dahl-Jensen et al. 1998
Greenland Borehole Temperature Dahl-Jensen et al. 1998: Greenland Borehole Temperature Dahl-Jensen et al. 1998
Slide42: Sidorova et al. 2007
Alaska Hadley CRU 3 (°C) Shift in 1977, but high natural variability: Alaska Hadley CRU 3 (°C) Shift in 1977, but high natural variability
Slide44: When Hemingway writes “Snows of Kilimanjaro”—half of the “snows” are already gone X Mass Gain in 2006
Molg and Kaser 2007
Slide45: Regional Snowpack, Central Andes, 1951-2005
Masiokas et al. 2006
Slide46: Antarctica Sea Ice Chapman, U.Illinois
Slide47: Antarctica Sea Ice Chapman, U.Illinois
Slide49: Schneider et al. 2006 Antarctica Thermometers Ice Cores
Slide50: Sea Level Rise?
Slide51: Rate of rise for last 50 Years:
IPCC 2007 9” / Century
Jevrejeva et al. 2006 9” / Century
Woppelmann et al. 2007 6” / Century
Slide52: Suzuki et al. 2005 + Thermal Expansion
+ Greenland melting
- Antarctica accumulation
Slide53: Extreme Weather?
Slide54: Oklahoma - record long period (> 100 days) without a tornado 2003-04
US Hurricanes: US Hurricanes 2001-2006
Slide56: Global Hurricane Activity
There has been no significant change in global net tropical cyclone activity (Klotzbach 2006)
Slide57: Bringing on prolonged drought, heat waves Greenhouse pollution: Utah warming faster than anywhere else on Earth!
By Patty Henetz
The Salt Lake Tribune
Gov. Huntsman commissioned the report on Aug. 25, 2006, with the specific instruction that it include a scientific report that was not subject to the same debate as the rest of the issues the council undertook.
Slide58: Droughts?
US: Blue = Fewer and Shorter Andreadis and Lettenmairer 2006
Evidence Thus Far: Evidence Thus Far Global surface temperature is rising, but in a way inconsistent with model projections of GHG forcing
Overall decline in ice mass, with sea level rise of about 1” per decade
Severe weather not becoming more frequent
Please don’t demonizing energy because: Without energy, life is brutal and short: Please don’t demonizing energy because: Without energy, life is brutal and short
Energy Technology: Energy Technology 1900: World supported
56 billion
human-life years
2005: World supports
429 billion
human-life years
Slide62: Kenya, East Africa
Slide63: Energy Transmission Energy System Energy Use Energy Source
The Dilemma of “doing something about global warming” : The Dilemma of “doing something about global warming” Meet significant growth in energy demand
Supply affordable energy
Benefits of energy are ubiquitous and innumerable. People want energy.
Health, security and longevity enhanced by affordable energy
Reduce CO2 emissions substantially so as to have a detectable impact on emissions (massive reductions) and thus “manage the climate”
What did California do?: 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
Question: Question What would be the impact on global surface temperatures of adopting and adhering to AB 1493?
Start with IPCC AR4 “Best Guess” scenario (A1B “business as usual”)
Adjust CO2 emissions to reflect adoption and adherence by (a) California, (b) the Northeast and (c) all of U.S.
Perform calculations so as to overestimate impact, not underestimate impact
IPCC “Best Estimate”: IPCC “Best Estimate”
California AB 1493 26% CO2 reduction LDV 2016: California AB 1493 26% CO2 reduction LDV 2016
Answers: Answers The answers indicated the impact would be so tiny as to be undetectable and immeasurable
If applied to the entire world, the net impact by 2100 would be no more than 0.03 °C, again, an undetectable amount
The impact on sea level rise would be 1 mm by 2100 if all U.S. adhered
Slide70: 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.” Judge William Sessions III Ruling 12 Sept 2007
AB 1493 is legal
Questions: 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)
IPCC “Best Estimate”: IPCC “Best Estimate”
Net Effect of 10% CO2 emission reduction to A1B Scenario (~1000 Nuclear Plants by 2020): Net Effect of 10% CO2 emission reduction to A1B Scenario (~1000 Nuclear Plants by 2020)
Answers about Nuclear Power: Answers about Nuclear Power By 2050, a reduction of global surface temperature by at most 0.07 °C
By 2100 a reduction of global surface temperature by at most 0.15 °C
Slide76: Main Points:
Without energy, life is brutal and short.
Proposed “do-something-about-global-warming” initiatives will not detectably alter whatever the climate is going to do.
A MORE RATIONAL APPROACH?: A MORE RATIONAL APPROACH? In 50 years will we learn that the most cost-effective path was to adapt to changes we actually observed and measured, rather than try to outguess Mother Nature’s course?
In 50 years will we be surprised not by climate change but by the inventive minds of our scientists and engineers, unfettered by mandates, as they discover profitable and affordable ways to generate energy without carbon emissions?
20th Century Transportation was de-horsified 21st Century Energy will be de-carbonized: 20th Century Transportation was de-horsified 21st Century Energy will be de-carbonized