Global Climate SimulationsWindows on the World of Tomorrow
Renewable Energy Summit, Milwaukee, Wisconsin, March 13, 2008
Mark A. ChandlerNASA Goddard Institute for Space Studiesat Columbia University
Fig. TS.2, IPCC 2007
Changes In Greenhouse Gases from Ice Core and Modern Data
CO2
CH4
N2O
Temperature retrievals from satellites now generally consistent with surface-based observations (except for the tropics)
Global Temperature Trends 1850-2005
Trend Length Years2550100150
Surface and TroposphereTrend Maps (1979-2005)
0.75-0.75°C per decade
What are Global Climate Models
and what do they project about the future?
Wind and Solar Climatologies
Computer Simulations of the Earth System
The GCM Grid
Increased Grid ResolutionRequires Increased Computing Power
Rule of thumb:10X more CPUfor a doubling ofresolution
Increased Resolution RequiresIncreased Computing Power
Circa 2000’s
Circa 1980’s
At every grid cell GCMs calculate:
Temperature (T)Pressure (P)Winds (U, V)Humidity (Q)
Fundamental Physical Quantities
T, P, U, V, and Q calculated and related to each other via:
GCM Fundamental Physical Equations
Seasonal and Diurnal CyclesLatent and Sensible Heat FluxesClouds and ConvectionPlanetary Boundary LayerGreenhouse GasesAerosolsSea IceGround HydrologyOcean Heat TransportOcean CirculationDynamic VegetationDynamic Ice SheetsCarbon Cycle Chemistry
Physical Processes Simulated by GCMs
Global_Warming_Sim2.R Model II 8/24/2000
Owner: Dr. Mark Chandler, [email protected]: Paleoclimate GroupThis experiment simulates climate change based on a1 percent/year increase in CO2
Object modules:MainC9 DiagC9 RadC9FFTC9UTILC9
Data input files:7=G8X10_600Ma9=NOV1910.rsf_snowball15=O8X10_600Ma19=CD8X10_600Ma23=V8X10_600Ma26=Z8X101_600Ma21=RTAU.G25L1522=RPLK2529=Snowball_Earth_Regions
Label and Namelist:Global_Warming_Sim2 (Transient increase in CO2)
&INPUTZ TAUI=10176.,IYEAR=1900, KOCEAN=1, SRCOR=.95485638151, S0X=1.,CO2=.31746031746031, USET=0.,TAUE=35040., USESLP=-12., ISTART=3,KCOPY=2,NDPRNT=-1,TAUE=10177.,TAUP=95616.,
C** INITIALIZE SOME ARRAYS AT THE BEGINNING OF SPECIFIED DAYS fName = './prt/'//JMNTH0(1:3)//CYEAR//'.prt'//LABEL1(
IF(JDAY.NE.32) GO TO 294 JEQ=1+JM/2 DO 292 J=JEQ,JM DO 292 I=1,IM 292 TSFREZ(I,J,1)=JDAY JEQM1=JEQ-1 DO 293 J=1,JEQM1 DO 293 I=1,IM 293 TSFREZ(I,J,2)=JDAY GO TO 296 294 IF(JDAY.NE.213) GO TO 296 JEQM1=JM/2 DO 295 J=1,JEQM1 DO 295 I=1,IM 295 TSFREZ(I,J,1)=JDAY C**** INITIALIZE SOME ARRAYS AT THE BEGINNING OF EACH DAY 296 DO 297 J=1,JM DO 297 I=1,IM TDIURN(I,J,1)=1000. TDIURN(I,J,2)=-1000.
TDIURN(I,J,6)=-1000.
PEARTH=FDATA(I,J,2)*(1.-FDATA(I,J,3)) IF(PEARTH.GT.0.) GO TO 297 TSFREZ(I,J,1)=365. TSFREZ(I,J,2)=365. 297 CONTINUE
So, What Is a GCM Really?A Computer Program
Unix Scripts Fortran Code
GCMs Require High-Level Programming Skills
and Supercomputing Resources
Distributed Computing Climate Experiments
DOE
GISSModel E
NASA
GISSModel E
NSF
GISSModel E
National Lab Supercomputing Resources
PersonalComputers
EdGCMModel E
SchoolLabs
EdGCMModel E
UniversityClusters
EdGCMModel E
GSFC GISS LangleyScientific
Community
SimulationDistribution
Simulation Results Collection
Primary Server
Perturbed Physics Ensembles
Desktop Client Computing Resources
NASA MAP Climate Scientists
“Big Iron” Computing
Scarsdale Teachers Institute Workshop, March 3 and 4, 2006
Climate Computing @ Home and School
What are the model inputs and where do they come from?
•Population Prospects•Economic Development•Energy Demand•Resource Availability•Technological Change•Future Energy Systems•Land Use•Environmental Policy
Google: IPCC SRES
IPCC Special Report on Emissions Scenarios (SRES)
Figure SRES 5-1
An Example of the Greenhouse Gas Emissions Scenarios
Carbon Dioxide Scenarios
Figure SPM-5
Figure SPM-6
IPCC 2007Atm-Ocn GCM Projections of Surface Air Temperatures
0.0 8.0°C
IPCC 2007Atm-Ocn GCM Projections of Surface Air Temperatures
Fig. TS.29
Continental Temperature Anomalies: Observations and Projections
IPCC, WG1, 2007
Model Ensemble Changes in Temperature, Precip, Storminess
Carbon Dioxide Change Over Geologic Time
Mid-Pliocene
The Last Global Warming vs. The Coming Global Warming
Pliocene Sea Surface Temperature Anomaly(January)
∆T = +2.09°C
Simulated Change in Surface Air Temperature(Annual Average)
∆T = +2.1°C
3 Mya
2005
Pliocene Temperature Change: 3 MYA
+2.13 °C
+2.33 °C
2050s
The Last Global Warming vs. The Coming Global Warming
The North AtlanticConundrum
Pliocene DATA
IPCC AOGCM
Impacts at ∆ Global Mean Temperature
(R. Warren, in “Avoiding Dangerous Climate Change” 2006)
• 1°C: world ocean and arctic ecosystems damaged• 1.5°C: Greenland ice sheet melting starts; ecosystems damaged in
many regions• 2°C: Agricultural yields fall, 1-3 billion experience water
stress, sea level rise displaces millions, malaria risks spread, Arctic ecosystems collapse, extinctions soar, 97% of coral reefs gone, global ecosystems lose 5-66% of their extent;
• 2-3°C: Amazon and other forests and grasslands collapse, adding to CO2 increase
• 3°C: Millions at risk to water stress, flood, hunger, dengue and malaria increase, few ecosystems can adapt, losing 7-74% of extent
• 4°C: whole regions forced out of agriculture (Australia), thermohaline circulation could collapse, West Antarctic Ice Sheet melting may begin, increases in extreme weather, 60% loss of tundra
http://data.giss.nasa.gov/cgi-bin/cdrar/do_LTmapE.py
21st Century Global Warming
Climate Simulations for IPCC 2007 Report
► Climate Model Sensitivity 2.0-5.0ºC for 2xCO2 (consistent with paleoclimate data & other models)
► Simulations Consistent with 1880-2003 Observations
Source: Hansen et al., to be submitted to J. Geophys. Res.
IPCC MAIN FINDINGS
Working Group I – The climate is warming and humans are causing it. (90% Certainty)
Working Group II – Impacts are occurring now as a consequence of human-caused climate change. Specific future impacts have been identified. A portfolio of adaptation and mitigation measures can diminish the risks associated with climate change.
Working Group III – There is substantial potential for mitigation. Projected costs are ~3% of global GDP in 2030. All sectors, as well as changes in lifestyle and behavior patterns, can contribute to climate change mitigation.
Pliocene Global Warming: Main Findings
Global warming was 2-3°C higher than modern, similar to projected temperatures in the latter half of the 21st century.
Sea level was approximately 25 meters higher than today, indicating probably complete loss (collapse?) of Greenland and West Antarctic ice sheets.
North Atlantic ocean was a key area of warming in past global warming scenarios in contrast to the IPCCC AOGCM estimates of future climate change. If model’s are underestimating the climate change impact in the N. Atlantic global warming could proceed more rapidly than our current projections.
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