What is the point of this session

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What is the point of this session?

• To use the UKs experience to give ideas about
  creating and using climate change scenarios in
  other countries and situations
• Not a talk on climate modelling!
• An overview of who, how, what and why
• Discussion of how these experiences apply to your
  own needs

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The next hour and a half..

• What are climate change scenarios and how have
  they featured in the UK?
• How have the UKCIP02 scenarios been created?
• Who are the major players?
• How have we dealt with uncertainties?
• Potential applications of the UKCIP02 scenarios
• How can the scenarios be improved?
• Lessons for the future
• Discussion

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What are scenarios?

• A scenario is
• a coherent, internally consistent and plausible
  description of a possible future state of the
  world (Parry and Carter, 1998)
• Not a forecast or a prediction
• A series of pictures of what the world could look
  like in the future

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Climate change scenarios

• Socio-economic futures (eg. population, economy,
  carbon intensity) - affects how GHG may change
• Climate modelling
• Result integrated scenarios - more sophisticated
  than pure climate modelling

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A history of UK Climate Change scenarios

• Climate Change Impacts Review Group of the DoE
  (CCIRG)
• 1991, 1996
• Presented a range of highly artificial
  global-scale scenarios (CO2 doubling)
• Tended to present a best guess based on 1980s
  Met Office UKTR model and HadCM1

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The 1998 UKCIP scenarios

• 1997 UK Climate Impacts Programme (UKCIP)
• 1998 Climatic Research Unit, Hadley Centre
  created UKCIP98 scenarios
• Wider range of variables and time-scales than
  CCIRG
• Range of four scenarios based on IS92a/IS92d
• HadCM2 model

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How have the UKCIP02 scenarios been created?
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UKCIP02 Climate Change Scenarios

• Geoff Jenkins
• Richard Jones
• Jason Lowe
• James Murphy
• David Hassell
• Penny Boorman
• Ruth McDonald
• Steven Hill

• Mike Hulme
• Xianfu Lu
• John Turnpenny
• Tim Mitchell

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UKCIP02 Climate Change Scenarios

• Funded by
• For

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The UKCIP02 Scenarios

• To be launched April 2002
• Revised scenarios using developments over past
  three years
• Explicitly linked to four socio-economic
  scenarios produced by IPCC
• Informed by the Third IPCC Climate Change
  Assessment Report

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• Uses more sophisticated HadCM3 and regional
  HadRM3 models (more greenhouse gas species,
  improved ocean and vegetation models)
• Much more detailed regional information (104 vs.
  4 grid boxes)
• 5 km observed data set
• Responses to users much more on extremes rapid
  climate change Gulf Stream uncertainty

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The SRES Scenarios
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Global carbon emissions - four IPCC scenarios
(2000 - 2100)
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Carbon dioxide concentrations IPCC scenarios
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The four UKCIP02 scenarios

• High Emissions A1FI
• Medium-High Emissions A2
• Medium-Low Emissions B2
• Low Emissions B1
• as inputs to Hadley Centres HadCM3 model
  (effective sensitivity 3.0 deg C)

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Global temperature (2000 - 2100)
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The Hadley Centre Global Climate Model (HadCM3)
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Hadley Centre Regional Climate Model (HadRM3)50
km grid
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What are UKCIP02s defining characteristics?

• It was GENERIC rather than for a SPECIFIC impacts
  project
• The centre of a policy network of groups with
  different aims
• Scenario range examined emissions uncertainty
  rather than uncertainty in the model

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What do the key players represent?

• DEFRA - funder government policy international
  obligations public perception
• UKCIP - scenario users (scientists, policymakers,
  impact assessments)
• Hadley - rigorous science basis of climate
  modelling
• Tyndall - leading the analysis and writing
  coordinating report production

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The results

• UKCIP02 had to balance needs of all the
  organisations
• Ease of communication vs. rigorous science vs.
  usefulness to impacts community
• Example - pattern-scaling

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Pattern-scaling

• Only A2 emissions, 2071-2100 means were modelled
• Other time periods and emissions scenarios were
  produced by scaling the model output patterns
• Scientifically less than rigorous
• But needed by the users (eg 2020s, 2050s)

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Interaction with other groups

• Hadley Centre modellers - storm surges/ocean
  modelling
• Land movement (Durham)
• Sea level (POL)

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What will happen to sea level?
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Sea level change Four IPCC scenarios
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Components of sea-level rise in 21st century
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Commitment to sea-level rise 600 years
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UK land movement (mm/yr) Source Ian Shennan
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How have we dealt with uncertainties?
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What uncertainties are there?

• Emissions - how will society change? We chose to
  explicitly include these in the range of
  scenarios
• Scientific - how do different models represent
  the environment? We have assessed the main
  scientific uncertainties and provided guidance on
  how to incorporate these

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UK temperature and precipitation (2080s)
comparison of models
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Winter temperature change with C-cycle (2080s,
Medium-High Emissions)
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Summer temperature change with C-cycle (2080s,
Medium-High Emissions)
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Methane concentrations - with and without climate
change feedbacks (A2 Emissions)
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Ozone concentrations - with and without climate
change feedbacks (A2 Emissions)
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Pattern-scaling

• Scientifically acceptable to scale HadRM3
  patterns with other models global temperatures?
  We decided not.
• Acceptable comparison between model and
  pattern-scaled results? Yes.

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HadRM2 vs. HadRM3Mean temperature change
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HadRM2 vs. HadRM3Precipitation change
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Daily maximum temperature HadRM3 (dotted) vs.
observations (solid)
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Potential applications of the UKCIP02 scenarios
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• Impacts, Adaptation, Vulnerability
• Informing Mitigation Policy
• Education and communication

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Lessons for the future
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Questions for discussion

• Who are your scenarios for?
• Who is funding them?
• How will they link climate and social science?
• Who is the most important player?
• How might the different powers interact?
• How will you communicate them to relevant groups
  and to the public?
• Are they user-friendly?
• Which government department is responsible, if
  any?