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INTERIM CLIMATE PROJECTIONS FOR THE SOUTHERN SLOPES Penny Whetton (on behalf of the NRM team) September 2014
Global temperatures have increased Each of the last three decades has been successively warmerat the Earth’s surface than any preceding decade since 1850.
The picture of a warming world The oceans are warming Sea level is rising Arctic sea ice is declining
2013 - Australia’s hottest year so far 2013 hottest year on record 0.17°C warmer than 2005 and hottest summer (2012/13) and warmest spring 2013 on record January heatwave: Hottest day on record for Australia: 40.3°C on 7 Jan 2013 Highest recorded temperature:49.6°C on 12 Jan 2013 in Moomba
Atmospheric carbon dioxide (CO2) The atmospheric concentrations of carbon dioxide, methane, and nitrous oxide have increased to levels unprecedented in at least the last 800,000 years.
Understanding climate change - observations Lean et al. (2010)
PROJECTIONS FOR AUSTRALIA When using these projections for decision making in NRM planning you should consider that different models and RCPs generate a range of projected future climates. The range of projections will be shown here.
The Climate System Climate is ‘averaged weather’, but it is influenced by many processes within the climate system. Current climate models are computer programs that simulate all these processes, as well as the weather itself Our projections are based ‘Coupled modelling intercomparison project –phase 5’, or CMIP5, on simulations of 40+ global climate models. Confidence is gained from their ability to reproduce observed features of current climate and past climate changes. Confidence in model estimates is higher for some climate variables (e.g., temperature) than for others (e.g., rainfall).
Weather and climate variability in climate models Weather and climate variability in models
Representative concentration pathways (RCPs) Four RCPs describe plausible trajectories of future greenhouse-gas and aerosol concentrations to the year 2100. These are named RCP2.6, RCP4.5, RCP6, and RCP8.5 in accordance with the range of radiative forcing values (in W/m2). Radiative forcing is a measure of the level of influence these gases have on the Earth’s energy balance. Each RCP is representative of a range of economic, technological, demographic, and policy futures. RCP4.5 and RCP8.5 concentration pathways are used for projections presented here.
Projected temperature compared to the 1986-2005 period. 2090 RCP8.5 Least warming (10th percentile) The latest model results (CMIP5) show higher rates of warming are anticipated in the central regions, and lower rates in the coastal and southern regions. This confirms findings from the earlier studies (CMIP3). Median warming (50th percentile) 4.4°C 4.2°C Most warming (90th percentile) Earlier results (CMIP3) Latest results (CMIP5) a) d) Least warming (10th percentile) Interim projections (08/2013) e) b) Median warming (50th percentile) Interim projections (08/2013) c) f) Most warming (90th percentile) Interim projections (08/2013) Projected temperature change (°C)
Projected rainfall Summer Percentage of models indicating an increase in rainfall over the 21st century (RCP8.5). Warmer colours (orange → red) indicate a rainfall decrease and blue colours, an increase in rainfall. Interim projections, 08/2013 Percent of models (40 CMIP5 models) Rainfall projections vary regionally with differing levels of agreement evident among models. More than 60 percent of models agree there will be an increase in rainfall in summer over parts of south-eastern Australia (blue shading). In some regions there is poor model agreement with regard to the direction of rainfall change (pale shading).
Projected rainfall Winter Percentage of models indicating an increase in rainfall over the 21st century (RCP8.5). Warmer colours (orange → red) indicate a rainfall decrease and blue colours, an increase in rainfall. Interim projections, 08/2013 Percent of models (40 CMIP5 models) Less than 10 percent of models indicate an increase in winter rainfall in south-west Western Australia and parts of southern Victoria (red shading). In some regions there is poor model agreement with regard to the direction of rainfall change (pale shading).
PROJECTIONS FOR SOUTHERN SLOPES CLUSTER REGION
Vic East + SE NSW Vic West In SS-Vic West But near border, so SS Vic East also relevant Tas East Tas West
Projected temperature: Southern Slopes Understanding interim projection plots Interim annual projected temperate change time series to 2100 for mid-range (RCP4.5; left) and high (RCP 8.5; right)
Understanding interim projection plots Bar-extensions represent the projected range (10th to 90th percentile) for individual years, taking into account year-to year variability in addition to the variability in the model response. Coloured bars represent different emission scenarios Bars show the range(10th to 90th percentile) of model simulations of 20-year average climate. Middle (bold) line is the median value of the model simulations over a 20-year average; half the model results fall above and half below this line. Compared to current conditions, for a given RCP scenario, the bar will move up or down to reflect the predominant direction of simulated change and will lengthen when models differ in their response.
Projected rainfall • Unlike changes in temperature, precipitation changes are not directly influenced by rising greenhouse gasses. • We also know that regional precipitation variations can be quite sensitive to small differences in the circulation and other processes, as is evident from the large natural variability of precipitation over Australia. • Therefore, with changing circulation in a warmer climate, different models can simulate somewhat different rainfall changes. Historical climate Intermediate (RCP 4.5) Highest (RCP 8.5)
Projected rainfall Range of projected seasonal rainfall for 2090 relative to the1986-2005period (grey bar) for intermediate (gold) and highest (pink) RCPs SSVW SSVE + SE NSW SSTW SSTE Increase Decrease Historical climate Intermediate (RCP 4.5) Highest (RCP 8.5)
Potential evapotranspiration Solar radiation Relative humidity Solar radiation increase is more likely than decrease in all four seasons, for intermediate and high RCPs. . Small decreases in relative humidity are projected during all four seasons, for intermediate and high RCPs, however there is a large spread of model simulations. Evapotranspiration is projected to increase in all seasons, with larger increases for the high than the intermediate RCP. Historical climate Intermediate (RCP 4.5) Highest (RCP 8.5)
Establishing The context The context What tree species will be planted in this bio-sequestration project? How large should the dam be? How will crop disease pressures change in future? How can I best preserve this wildlife corridor’? Will I upgrade my irrigation infrastructure? What varieties of crop might be more suitable in future? Where should I purchase my new farm? What is the habitat suitability for this species of frog? What are the stakeholders concerns / issues / decisions??
Risk analysis: future changes • What time frame that you are interested in.
Establishing the context e.g. What tree species will be suitable for bio-sequestration planting in future? Communication and consultation Monitoring and review Risk assessment Risk identification e.g. Identify thresholds (water access, temperature extremes, fire) Risk analysis e.g. address different planning horizons and potential future scenarios Risk evaluation e.g. ranking future climate impacts or benefit. and identify investment priorities Risk treatment e.g. planting suitable tree species. Process
Conclusions Navigating the maze of information about climate change science is challenging. There are many robust findings about the science. These provide a basis for action through adaptation and reducing emissions. Understanding the range of projected future change will inform prudent adaptation actions. By Richard Gifford
CSIRO advises that the information contained in this publication comprises general statements based on scientific research. The reader is advised and needs to be aware that such information may be incomplete or unable to be used in any specific situation. No reliance or actions must therefore be made on that information without seeking prior expert professional, scientific and technical advice. To the extent permitted by law, CSIRO (including its employees and consultants) excludes all liability to any person for any consequences, including but not limited to all losses, damages, costs, expenses and any other compensation, arising directly or indirectly from using this publication (in part or in whole) and any information or material contained in it. CONTACT US Penny Whetton e Penny.Whetton@csiro.au