INTERIM CLIMATE PROJECTIONS FOR THE SOUTHERN SLOPES Penny Whetton (on behalf of the NRM team) SEPTEMBER 2014 GLOBAL CONTEXT Global temperatures have increased Global temperatures have increased Each of the last three decades has been successively warmer at 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 Australian temperatures have risen 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) o Four RCPs describe plausible trajectories of future greenhousegas and aerosol concentrations to the year 2100. o 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 (10th percentile) Least warming Least warming Most warming (50th percentile) c) 4.4°C Median warming b) Latest results (CMIP5) (90th percentile) (50th percentile) Median warming Most warming a) (90th percentile) (10th percentile) Earlier results (CMIP3) d) Interim projections (08/2013) e) 4.2°C Interim projections (08/2013) f) Interim projections (08/2013) Projected temperature change (°C) 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). PROJECTED RAINFALL Summer Percentage of models indicating an increase in rainfall over the 21st century (RCP8.5). Interim projections, 08/2013 Warmer colours (orange → red) indicate a rainfall decrease and blue colours, an increase in rainfall. 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). Interim projections, 08/2013 Warmer colours (orange → red) indicate a rainfall decrease and blue colours, an increase in rainfall. 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 West In SS-Vic West But near border, so SS Vic East also relevant Tas West Vic East + SE NSW Tas East 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 Coloured bars represent different emission scenarios Bars show the range (10th to 90th percentile) of model simulations of 20-year average climate. 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. 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 the 1986-2005 period (grey bar) for intermediate (gold) and highest (pink) RCPs SSVW SSVE + SE NSW Historical climate Intermediate (RCP 4.5) Highest (RCP 8.5) Increase SSTE Decrease SSTW SOLAR RADIATION RELATIVE HUMIDITY POTENTIAL EVAPOTRANSPIRATION 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) Solar radiation increase is more likely than decrease in all four seasons, for intermediate and high RCPs. . USING PROJECTIONS INFORMATION ESTABLISHING THE CONTEXT What tree species will be planted in this bio-sequestration project? Will I upgrade my irrigation infrastructure? Where should I purchase my new farm? The context How will crop disease pressures change in future? What varieties of crop might be more suitable in future? How large should the dam be? How can I best preserve this wildlife corridor’? What is the habitat suitability for this species of frog? What are the stakeholders concerns / issues / decisions?? Risk analysis: future changes o What time frame that you are interested in. Establishing the context 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 Monitoring and review Communication and consultation e.g. What tree species will be suitable for bio-sequestration planting in future? 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 CONTACT US Penny Whetton e [email protected] 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. 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