Aldo Drago

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Estimating the future climate in the Maltese
Islands
Aldo Drago Physical Oceanography
Unit IOI-Malta Operational Centre University of
Malta
National Communication to the UNFCCC 2nd
Workshop for WG II III
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• CAUSES OF CLIMATE
• CHANGE
• HUMAN (ANTHROPOGENIC) FACTORS
• Greenhouse gases (CO2, CH4, etc.)
• Sulphur dioxide and other aerosol
• precursors
• NATURAL FACTORS
• External forcing (solar, volcanoes, etc.)
• Internally-generated variability

National Communication to the UNFCCC 2nd
Workshop for WG II III
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• CAUSES OF CLIMATE CHANGE

National Communication to the UNFCCC 2nd
Workshop for WG II III
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• PREDICTING FUTURE CLIMATE CHANGE
• Predict future socioeconomic changes
• Use these to predict future emissions
• From these predict changes in
• atmospheric composition
• Use these results to drive a climate
• model
• THESE ARE THE FIRST STEPS IN AN INTEGRATED
  ASSESSMENT OF THE CLIMATE PROBLEM

National Communication to the UNFCCC 2nd
Workshop for WG II III
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• CLIMATE CHANGE ASSESSMENT
• What it involves
• Identifying the causes of climate change
• Projecting future emissions
• Projecting future climate
• Estimating consequences/impacts
• Adaptation (reducing the impacts)
• Mitigation (reducing climate change)
• Policy options/mechanisms

National Communication to the UNFCCC 2nd
Workshop for WG II III
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• THE SRES EMISSIONS SCENARIOS
• (The basic drivers for future climate change)
• The Intergovernmental Panel on Climate Change
  (IPCC) has sponsored production of a new set of
  no-climate-policy emissions scenarios for GHGs,
  sulfur dioxide, and other gases
• These scenarios are based on a range of
  assumptions regarding future population, economic
  growth, energy technology growth, etc.
• The scenarios are published in a Special Report
  on Emissions Scenarios hence the acronym SRES
• (Special Report on Emissions Scenarios, eds.
  N.Nakicenovic and R. Swart, Cambridge University
  Press, 2000)

National Communication to the UNFCCC 2nd
Workshop for WG II III
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• FUTURE EMISSIONS
• IPCC SPECIAL REPORT ON EMISSIONS SCENARIOS
• GASES CONSIDERED
• CO2
• CH4
• N2O
• SO2
• Reactive gases (CO, NOx, VOCs)
• Halocarbons (CFCs, HCFCs, HFCs,
• PFCs, SF6)

National Communication to the UNFCCC 2nd
Workshop for WG II III
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TAR vs SAR
National Communication to the UNFCCC 2nd
Workshop for WG II III
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PREDICTING FUTURE CLIMATE
National Communication to the UNFCCC 2nd
Workshop for WG II III
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KEY UNCERTAINTIES (For explaining the past,
predicting future anthropogenic climate change,
or both) (1) Future emissions (2) The climate
sensitivity (3) Heat flux into the
ocean (4) Radiative forcing due to
aerosols (5) Solar and volcanic
forcing (6) Carbon cycle/climate
feedbacks (7) Changes in ocean circulation The
climate sensitivity determines how much the
climate will change for a given change in
atmospheric composition. It is usually expressed
as the eventual global-mean warming for a
doubling of the CO2 concentration, and lies in
the range 1.5-4.5oC.
National Communication to the UNFCCC 2nd
Workshop for WG II III
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DEVELOPING SCENARIOS FOR REGIONAL CLIMATE
CHANGE (1) Select emissions scenario, climate
model parameters (most importantly, the climate
sensitivity), and future date (2) Use these to
predict future global-mean temperature (and
its uncertainty range) (3) Select variable
(e.g., annual-mean temperature, winter
precipitation, etc.) (4) Select models to define
normalized patterns of change (i.e. change per
unit global-mean warming). Use a single model, or
the average of a set of models (5) Scale up
normalized pattern using predicted
global-mean temperature change
National Communication to the UNFCCC 2nd
Workshop for WG II III
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SOURCES OF UNCERTAINTY Regional Scale (1)
Uncertainties in global-mean temperature (due to
uncertainties in emissions, climate sensitivity,
etc.) (2) Uncertainties in normalized patterns
of change i.e., patterns of change per unit
global-mean warming (quantifiable by comparing
results from different models)
National Communication to the UNFCCC 2nd
Workshop for WG II III
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THE MAGICC/SCENGEN SOFTWARE Global-mean
component Model for the Assessment of
Greenhouse-gas Induced Climate Change -
MAGICC Regional climate component SCENario
GENerator - SCENGEN
National Communication to the UNFCCC 2nd
Workshop for WG II III
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National Communication to the UNFCCC 2nd
Workshop for WG II III
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THE MAGICC SOFTWARE
Library of Emissions Scenarios
Gas Cycle Models
User Choices of Model Parameters
Atmospheric Composition Changes
Global-mean Temperature And Sea Level Model
User Choices Of Model Parameters
Global-mean Temperature and Sea Level Output
TO SCENGEN
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National Communication to the UNFCCC 2nd
Workshop for WG II III
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National Communication to the UNFCCC 2nd
Workshop for WG II III
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THE SCENGEN SOFTWARE
Global-mean Temperature from MAGICC
Library of GCM Data Sets
User Choices GCMs to use, Future Date, Region,
etc.
Regionalization Algorithm
Library of Baseline Climatology Data (1961-90)
Regional Climate or Climate Change Output
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National Communication to the UNFCCC 2nd
Workshop for WG II III
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National Communication to the UNFCCC 2nd
Workshop for WG II III
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• LIMITATIONS OF MAGICC/SCENGEN
• Coarse resolution
• Rather old GCM data
• Based on SAR science
• Rather crude downscaling techniques
• Reliance on pattern-scaling methods
• Mitigation (reducing climate change)
• Inability to treat interannual variability

National Communication to the UNFCCC 2nd
Workshop for WG II III
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• APPLICATION TO THE
• MALTESE ISLANDS
• (1) Generate normalised patterns of change for
  selected parameters using MAGICC/SCENGEN
• Single and multiple model experiments
• Effects of aerosol forcing
• Updated emissions scenarios
• (no-climate-policy scenario SRES A1B-AIM)

National Communication to the UNFCCC 2nd
Workshop for WG II III
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National Communication to the UNFCCC 2nd
Workshop for WG II III
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HadCM2 characteristics HadCM2 is a coupled
atmosphere-ocean general circulation model
developed at the Hadley Centre Johns et al.
(1997). It has a stable and realistic control
climatology, using flux adjustment, and has been
used for a wide range of climate-change
experiments. HadCM2 has a spatial resolution of
2.5 latitude by 3.75 longitude, equivalent to a
surface resolution of about 417 km x 278 km at
the Equator, reducing to 295 km x 278 km at 45
degrees of latitude The atmospheric component of
HadCM2 has 19 levels and the ocean component
20. The equilibrium climate sensitivity of
HadCM2, that is the global-mean temperature
response to a doubling of effective CO2
concentration, is approximately 2.5C, although,
this quantity varies with the time-scale
considered. This is somewhat lower than most
other GCMs.
National Communication to the UNFCCC 2nd
Workshop for WG II III
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• APPLICATION TO THE
• MALTESE ISLANDS
• (cont.)
• (2) Scaling the change patterns
• Global-mean warming projections
• using TAR science
• Expressed in probabilistic values
• Different emissions scenarios
• Account for most important
• uncertainties

National Communication to the UNFCCC 2nd
Workshop for WG II III
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PROBABILISTIC DESCRIPTION OF GLOBAL WARMING
Percentile values for global-mean warming (oC)
from 1986 to the year indicated
National Communication to the UNFCCC 2nd
Workshop for WG II III
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Evolution of uncertainties in global-mean
warming, illustrated by warming distributions
over 1990 2030 (blue), 1990 2070 (green), and
1990 2100 (red). This is the log-normal
sensitivity case with carbon cycle, ocean mixing,
and aerosol forcing uncertainties included. The
bar under the x-axis shows the IPCC TAR 1990
2100 warming range. Reproduced from Wigley
Raper, 2001).
National Communication to the UNFCCC 2nd
Workshop for WG II III
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Expected Annual-Mean Air Temperature Rise for the
Maltese Islands
National Communication to the UNFCCC 2nd
Workshop for WG II III
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National Communication to the UNFCCC 2nd
Workshop for WG II III
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National Communication to the UNFCCC 2nd
Workshop for WG II III
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Mean temperature (oC) and monthly precipitation
(mm) for the 5o latitude/longitude grid box
containing the Malta Islands (37.5o N 12.5o E).
Precipitation values are indicated in the bar
chart, whilst the continuous line represents mean
temperature. Observed present values (averaged
for the period 1971 2000) are indicated in
blue, whilst red corresponds to the scenario
constructed using the HadCM2 pattern with aerosol
effects, scaled according to the 50 percentile
of global-mean temperature change from the IPCC
TAR over 1986 to 2100. For reference the dotted
curve gives the scaling according to the 95
percentile global-mean temperature change.
National Communication to the UNFCCC 2nd
Workshop for WG II III
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National Communication to the UNFCCC 2nd
Workshop for WG II III
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Expected Percentage Decrease in Annual
Precipitation for the Maltese Islands
National Communication to the UNFCCC 2nd
Workshop for WG II III
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National Communication to the UNFCCC 2nd
Workshop for WG II III
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National Communication to the UNFCCC 2nd
Workshop for WG II III
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Mean temperature (oC) and monthly precipitation
(mm) for the 5o latitude/longitude grid box
containing the Malta Islands (37.5o N 12.5o E).
Precipitation values are indicated in the bar
chart, whilst the continuous line represents mean
temperature. Observed present values (averaged
for the period 1971 2000) are indicated in
blue, whilst red corresponds to the scenario
constructed using the HadCM2 pattern with aerosol
effects, scaled according to the 50 percentile
of global-mean temperature change from the IPCC
TAR over 1986 to 2100. For reference the dotted
curve gives the scaling according to the 95
percentile global-mean temperature change.
National Communication to the UNFCCC 2nd
Workshop for WG II III
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National Communication to the UNFCCC 2nd
Workshop for WG II III
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Expected normalised change in key meteo
parameters for the Maltese Islands
National Communication to the UNFCCC 2nd
Workshop for WG II III
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Summary of climate change projections for the
Maltese Islands
TEMPERATURE At the annual level the sensitivity
of temperature to the enhanced greenhouse effect
is higher than the global sensitivity by about
9 Seasonal sensitivities are higher than the
global increase throughout the year except in the
period March - May 50 probability that warming
will be 3oC by end of century seasonal patterns
will be retained with a practically uniform
warming over all months
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...Continued

• PRECIPITATION
• 50chance of about 17 change in annual total by
  2100
• Decrease in autumnincrease in spring
• Predicted range of possible changes lies well
  within the
• range of climate variability
• Overall result
• Moderate impact of climate change
• Rainfall decrease on a yearly basis
• shift to slightly more rain in winter and less in
  autumn
• slight reduction in water supply, higher
  temperatures
• and more evapotranspiration

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Contacts
Physical Oceanography Unit Aldo Drago IOI-Malta
Operational CentreUniversity of Maltac/o 36,
Old Mint Street VLT12 MALTATel./Fax 356
21232493aldo.drago_at_um.edu.mt
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Most Recent Updates

• MedGOOS Secretary
• Aldo Drago
• IOI-Malta Operational CentreRoom 303, University
  of MaltaMsida MSD06 - MALTATel 356 21241176
  ext 204/243Fax [phone]genmcst_at_keyworld.ne
  t
• In the last decade precipitation increased by
  0.5 -1 / decade in
• the continental regions with medium to high
  latitudes in the
• northern hemisphere
• Precipitation decreased by 0.3/ decade in the
  subtropical regions
• (10N-30N)
• In the last 50 years there was an increase of
  2-4 in the frequency
• of occurrence of extreme rain events and an
  increase of about 2
• in cloud cover during the last decade
• in the last 50 years there was a decrease in
  events of extreme low temperatures and a slight
  increase in events of extreme high temperatures