User-friendly software for estimating future changes in climate

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					  User-friendly software for estimating future
changes in climate and associated uncertainties


                    Tom Wigley
     National Center for Atmospheric Research,
              Boulder, CO 80307, USA

                    wigley@ucar.edu

       Presented at ABARE Outlook 2006 Conference,
                        Canberra.
                       Feb. 28, 2006
 THE MAGICC/SCENGEN SOFTWARE
The software combines a relatively simple coupled gas-
  cycle/climate model (MAGICC) to give information about
  future global-mean temperature and sea level rise …..



with a scaling algorithm (SCENGEN) and a library of observed
  data sets and results from coupled Atmosphere/Ocean
  General Circulation Models to give information about the
  regional details of future climate.
   MAGICC/SCENGEN: PURPOSE


The purpose of this software is to allow non-expert users
to investigate the implications of different emissions
scenarios for future global-mean and regional climate
change and to investigate uncertainties
What is MAGICC?

Model for the Assessment of Greenhouse-gas Induced
Climate Change

MAGICC is the climate model that has been used in all
IPCC assessments to produce projections of global-
mean temperature and sea level change.
What is SCENGEN?

SCENGEN is a climate SCENario GENerator.

SCENGEN uses the output from MAGICC to produce
maps showing the regional details of future climate.
QUESTIONS MAGICC/SCENGEN CAN ANSWER
• How will global-mean temperature or sea level change for a given emissions scenario?

• What are the uncertainties in such projections?

• What must we do to stabilize greenhouse-gas concentrations?

• What would happen if we stabilized emissions at present levels?

• How will climate patterns/regional details change for different emissions scenarios?

• How will climate variability change?

• How different are the results from different climate models?

• What is the probability of an increase/decrease in precipitation at a given location?
Emissions output
from Integrated    MAGICC FLOWCHART
Assessment
Model, or ….
                                     User Choices
                      Gas Cycle       of Gas-Cycle
                       Models            Model
 Selection from
                                       Parameters
   Library of
  Emissions
   Scenarios
                      Atmospheric
                      Composition
                       Changes


                     Global-mean     User Choices
                      Temperature     of Climate
                     And Sea Level       Model
                         Model        Parameters


                      Global-mean
                      Temperature
                     and Sea Level
                         Output      TO SCENGEN
PRIMARY INPUT:
Two emissions scenarios (nominally a baseline ‘no-climate-policy’
scenario and a ‘policy’ scenario). The purpose here is to be able
to assess the influence of a mitigation policy on climate.


GASES CONSIDERED:

CO2
CH4
N2O
SO2
Reactive gases (CO, NOx, VOCs)
Halocarbons (CFCs, HCFCs, HFCs, PFCs, SF6)
Examples of results from MAGICC



 Results from the IPCC Third Assessment Report

Probabilistic projections of global-mean temperature
MAGICC projections in the IPCC TAR
    MAGICC: Primary Sources of Uncertainty


Emissions (all GHGs, SO2, reactive gases, etc.)

Climate sensitivity (equilibrium warming for 2xCO2)

Ocean mixing (diffusivity, THC changes)

Carbon cycle feedbacks (CO2 fertilization, climate)

Aerosol forcing (sulphate, soot, etc.)
                               Probabilistic results with MAGICC
                               1.8
                                           1990-2030         PROBABILISTIC PROJECTIONS OF GLOBAL
PROBABILITY DENSITY (( C)-1)
                               1.6                                         WARMING


                               1.4
                     o




                               1.2

                                1

                               0.8
                                                           1990-2070
                               0.6

                               0.4
                                                                        1990-2100
                               0.2

                                0                                                                          TAR RANGE
                                     0     1           2          3     4           5    6             7
                                                                                                   o
                                     GLOBAL-MEAN TEMPERATURE CHANGE FROM 1990 ( C)
                  SCENGEN FLOWCHART

Global-mean Temperature
      from MAGICC


                                             User Choices:
   Library of                               AOGCMs to use,
AOGCM Data Sets                               Future Date,
                       Regionalization:       Region, etc.
                      (Scaling Algorithm)

   Library of
    Baseline
  Climatology
 Data (1961-90)                                Regional
                                               Climate or
                                            Climate Change
                                                Output
Examples of results from SCENGEN
Examples of results from SCENGEN



          Patterns of temperature change
          Patterns of precipitation change
        Probability of a precipitation increase
   Differences between different climate models
Warming pattern in 2050 under the A1B scenario
Normalized warming pattern
  (i.e., per 1oC global-mean warming)
Precipitation changes in 2050 under the A1B scenario
Probability of a precipitation increase
      Differences between different
                AOGCMs



TThese are results for normalized patterns of change – i.e.,
  change per 1oC global-mean warming. This eliminates
  inter-model differences arising from differences in the
  climate sensitivity. s removes the effect of
  differences in model climate sensitivities and
  focuses on differences in the spatial patterns of
  climate change.
Annual precipitation change: BMRC AOGCM
Annual precipitation change: Cerfacs AOGCM
Annual precipitation change: GISS AOGCM
             Summary/Conclusions

The MAGICC software allows one to emulate and expand
  upon global-mean temperature and sea level projections
  given by IPCC, and to investigate uncertainties in these
  projections.
The software runs in seconds on a laptop computer.
SCENGEN provides access to climate change results from a
  wide range of AOGCMs and allows one to compare or
  combine results from these AOGCMs.
MAGICC/SCENGEN may be downloaded from …
                     www.cgd.ucar.edu