Carbon dioxide concentrations over the last 800,000 years CO2 (ppm) 400 380 360 340 320 300 280 260 240 220 200 Atmospheric CO2 concentrations reached 395 parts per million in 2013 Carbon dioxide concentrations over the last 800,000 years 700 600 500 400 300 200 100 Thousands of years ago

The State of the Climate report Joint Bureau and CSIRO publication Previous reports, 2010 and 2012 Seeks to convey complex information to a general audience Accompanied by further material online

Evidence of climate change is unequivocal Evidence that the Earth’s climate continues to warm is unequivocal. Multiple lines of evidence indicate that it is extremely likely that the dominant cause of recent warming is human-induced greenhouse gas emissions and not natural climate variability. Placeholder / mock up to indicate concept. 4

Carbon dioxide emissions Most of the CO2 emissions from human activities are from fossil-fuel combustion and land-use change (top graph). Emissions are expressed in gigatonnes of carbon (C) per year. A gigatonne is equal to 1 billion tonnes. One tonne of carbon (C) equals 3.67 tonnes of carbon dioxide (CO2). CO2 emissions from human activities have been taken up by the ocean (middle graph, in blue, where negative values are uptake), by land vegetation (middle graph, in gold), or remain in the atmosphere. There has been an increase in the atmospheric concentration of CO2 (bottom graph, in red), as identified by the trend in the ratio of different types (isotopes) of carbon in atmospheric CO2 (bottom graph, in black, from the year 1000). CO2 and the carbon-13 isotope ratio in CO2 (δ13C) are measured from air in Antarctic ice and firn (compacted snow) samples from the Australian Antarctic Science Program, and at Cape Grim (northwest Tasmania).

Changes in the global climate system Global mean temperature has risen by 0.85˚C from 1880 to 2012. The amount of heat stored in the global oceans has risen, and global mean sea level has increased 225 mm from 1880 to 2012. 1. With regional variation (almost all glaciers worldwide losing mass but some gaining) but overall net loss. 2. With regional variation (large loss in the Arctic, small net gain in the Antarctic) but overall net loss.

Evidence of climate change is unequivocal Warming of the world’s oceans accounts for more than 90% of additional energy accumulated from the enhanced greenhouse effect. Placeholder / mock up to indicate concept. 7

Ocean heat content Change in ocean heat content (in joules) from the full ocean depth, from 1960 to present. Shading provides an indication of the confidence range of the estimate. 8

Sea level High-quality global sea-level measurements from satellite altimetry since the start of 1993 (orange line), in addition to the longer-term records from tide gauges (green line, with shading providing an indication of the confidence range of the estimate). Inset: Sea-level increase since 1993 from the satellite altimetry. The light green line shows the monthly data, the dark green line the three-month moving average, and the orange line the linear trend. 9

Warming trends Australia’s climate has warmed, and the frequency of extreme weather has changed, with more extreme heat and less extreme cold. Placeholder / mock up to indicate concept.

Annual mean temperature changes across Australia since 1910.

Sea-surface and surface air temperature Time series of anomalies in sea-surface temperature and temperature over land in the Australian region. Anomalies are the departures from the 1961–1990 average climatological period. Sea-surface temperature values are provided for a region around Australia (from 4°S to 46°S and from 94°E to 174°E).

Distribution of monthly temperatures Distribution of monthly maximum temperature (left) and monthly minimum temperature (right), expressed as anomalies (standardised), aggregated across 104 locations and all months of the year, for three periods: 1951–1980 (pink, grey), 1981–2010 (orange, green) and 1999–2013 (red, blue). Means and standard deviations used in the calculation of the standardised anomalies are with respect to the 1951–1980 base period in each case. Very warm and very cool months correspond to two standard deviations or more from the mean. The vertical axis shows how often temperature anomalies of various sizes have occurred in the indicated periods.

We are setting more temperature records The frequency of cold records has declined The frequency of hot records has increased dramatically since 1900 Number of coldest on records Number of hottest on records Photo: Credit: Ian Forrest, Bureau of Meteorology. 14

Exceptional heat is becoming more frequent Number of days when the national temperature was in the hottest (99th) percentile Number of days each year where the Australian area-averaged daily mean temperature is above the 99th percentile for the period 1910–2013. The data are calculated from the number of days above the climatological 99th percentile for each month and then aggregated over the year. This metric reflects the spatial extent of extreme heat across the continent and its frequency. Half of these events have occurred in the past twenty years. 15

Summer heatwaves Black Saturday 2009 heatwave January 2013 heatwave Record-breaking heatwave across southeastern Australia January 2013 heatwave Over 70% of the continent recording temperatures in excess of 42 °C Maximum temperatures – 27 Jan – 8 Feb 2009 January 7th and 8th set record Australian mean temperature of 32.22°C and 32.32°C, well above previous high of 31.86°C, set in 1972. First two weeks of January 2013 now hold the records for every hottest sequential-days stretching from one to 14 days for daily mean temperatures It’s the duration of this event and the widespread nature. If we think back to the 2009 Black Saturday fires – it was the record heatwave the week before and the period of drought for the preceding 10 years that set up the catastrophic fires. This time we didn’t have the long lead of drought, but the temperatures have been so exceptional that even the experienced fire and land use experts were amazed at the drying that has occurred. We didn’t get the same meteorological set up in terms of the winds; but I suggest that due to a combination of good planning, good environmental intelligence and really, some plain old luck in terms of where the fires occurred, we were spared so far this year. But the fires down in Dunalley in Tasmania showed what might have occurred. 476 weather station records and 17 national and State area-average records. Maximum temperatures – first half of Jan 2013 16

2013, a year of heatwaves Days > 99th percentile for average temperature: 1911-1950: 20 days 2013: 23 days Heatwave frequency, duration and intensity increasing Dry upper layer soils; less evaporative cooling, lower heat capacity High frequency of heatwaves in 2013 1911-1950: 20 days average temperature > 99th percentile. 2013: 23 days 17

Increased rainfall? Rainfall averaged across Australia has slightly increased since 1900, with the largest increases in the northwest since 1970. Placeholder / mock up to indicate concept. 18

Northern wet season (Oct-Apr) rainfall deciles since 1995-96 Increased rainfall? Northern wet season (Oct-Apr) rainfall deciles since 1995-96 Northern wet season (October–April) rainfall deciles since 1995–96. A decile map shows the extent that rainfall is above average, average or below average for the specified period, in comparison with the entire national rainfall record from 1900. The northern wet season is defined as October to April by the Bureau of Meteorology.

Drying across the south Rainfall has declined since 1970 in the southwest, dominated by reduced winter rainfall. Autumn and early winter rainfall has mostly been below average in the southeast since 1990. Placeholder / mock up to indicate concept. 20

Drying across the south Southern wet season (Apr-Nov) rainfall deciles since 1996 Southern wet season (April–November) rainfall deciles since 1996. A decile map shows the extent that rainfall is above average, average or below average for the specified period, in comparison with the entire rainfall record from 1900. The southern wet season is defined as April to November by the Bureau of Meteorology.

More fire weather There has been an increase in extreme fire weather, and a longer fire season, across large parts of Australia since the 1970s. Placeholder / mock up to indicate concept. 22

More fire weather, a longer fire season Forest fire danger index (FFDI) Trends 1973-2010 The map shows the trends in extreme fire weather days (annual 90th percentile of daily FFDI values) at 38 climate reference sites. Trends are given in FFDI points per decade and larger circles represent larger trends. Filled circles represent trends that are statistically significant. One location, Brisbane Airport, shows a non-significant decrease. Time series showing the increasing trend in the annual cumulative Forest Fire Danger Index (FFDI) at Melbourne Airport. A long-term trend is discernible despite significant annual variability. 23

Projections for Australia Placeholder / mock up to indicate concept. 24

Some future warming is now certain Historical RCP2.6 RCP4.5 RCP6.0 RCP8.5 Global-mean temperature Temperature (Celsius) Emissions scenarios make little difference to 2050 Year 25

Australian climate projections for 2100 Annual temperature change temperature April to September rainfall change rainfall RCP2.6 RCP8.5 RCP2.6 RCP8.5 Low emissions High emissions Low emissions High emissions Temperature change in degrees for 2081–2100 with respect to 1986–2005 Percentage rainfall change for 2081–2100 with respect to 1986–2005 this is from the ipcc atlas (Annex 1). Hatching: Hatching indicates regions where the magnitude of the change of the 20-year mean is less than one standard deviation of model-estimated present-day natural variability of 20-year mean differences. The natural variability is estimated using all pre-industrial control runs which are at least 500 year long. The first 100 years of the pre-industrial are ignored. The natural variability is then calculated for every grid point as the standard deviation of non-overlapping 20-year means after a quadratic fit is subtracted at every grid point to eliminate model drift. This is multiplied by the square root of 2, a factor that arises as the comparison is between two distributions of numbers. The median across all models of that quantity is used. This characterizes the typical difference between two 20-year averages that would be expected due to unforced internal variability. The hatching is applied to all maps so, for example, if the 25th percentile of the distribution of model projections is less than one standard deviation of natural variability, it is hatched. The hatching can be interpreted as some indication of the strength of the future anomalies from present-day climate, when compared to the strength of present day internal 20-year variability. It either means that the change is relatively small or that there is little agreement between models on the sign of the change. It is only presented as a guide to assessing the strength of change as the difference between two 20-year intervals. Using other measures of natural variability would give smaller or larger hatched areas, but the colours underneath the hatching would not be very different. Other methods of hatching and stippling are possible (see Box 12.1) and, in cases where such information is critical, it is recommended that thorough attention is paid to assessing significance using a statistical test appropriate to the problem being considered.

Projections of Australian annual temperature Observed annual temperature in white RCP4.5 projected annual temperature This is the observed Australian annual temperature curve animated in black, over-layed against 13 different climate models (CMIP 5, upcoming IPCC fifth assessment) in red. Australia has warmed since 1950. It is interesting for a lay audience to note how well the climate models do in capturing mean temperature changes, as well as the spikes of hot years and cold years. The model knows nothing about the real world except for greenhouse gas and aerosol forcing – i.e. it is not trained or forced with observations – so the spikes do not correspond to the observations (i.e. they do not occur in the same years). Australia’s warmest year is the spike seen in 2005 – just over 1 degree above 1961-1990 average (1.03). This translates to a very cool year by 2050. The last decade has been associated with a high frequency of extreme heat conditions during summer and increased fire weather, as well as loss of snow and frost. The longer such conditions persist, the more environmental change the country will experience – with longer and more frequent heatwaves. Having these conditions sit at the cooler end of normal in 40 years time is obviously significant, with extreme conditions such as the 2009 Black Saturday heatwave and the 2013 January heatwave becoming the norm (i.e. average) in the second half of the 21st century. 27

Small shifts, but potential change in climate zones Wimmera Central Victoria Climatological rainfall map based on around 2 degrees of warming and more than 20% drier Photo (bottom left): Credit: Department of Foreign Affairs and Trade. I could have shown four degrees, but it’s a little abstract. Its almost trivialising to see a map getting redder. So what I have done here is show the impact of changing climate zones. Lets look at a high end (hot and dry) and look at a target location- in this case Adelaide. Current climate images -- showing a variable Mediterranean climate and landscape, sometimes wetter sometimes drier – but still having an average. The images here show that – there is some overlap between climate zones but that the mean change is significant. By about mid century in the upper warming projections- central Vic becomes more like the Wimmera at 2 degrees warmer and > 20% drier. This shows that small shifts, *if they exist for long enough*, cause very different landscapes and environments. Even a half degree in temp or 10% change in rainfall can mean a very different climatological and vegetation zone. We are talking about future changes that are greater than the difference between one climate zone and another. And it’s the pace of this change that has most scientists worried- you rarely push things along this quickly in the geological record. 28

Small shifts, but potential change in climate zones Central Darling Wimmera Climatological rainfall map based on around 2 degrees of warming and more than 20% drier Photo (bottom left): Credit: Department of Foreign Affairs and Trade. I could have shown four degrees, but it’s a little abstract. Its almost trivialising to see a map getting redder. So what I have done here is show the impact of changing climate zones. Lets look at a high end (hot and dry) and look at a target location. The images here show that – there is some overlap between climate zones but that the mean change is significant. By about mid century in the upper warming projections- Wimmera becomes more like the Central Darling at 2 degrees warmer and > 20% drier. This shows that small shifts, *if they exist for long enough*, cause very different landscapes and environments. Even a half degree in temp or 10% change in rainfall can mean a very different climatological and vegetation zone. We are talking about future changes that are greater than the difference between one climate zone and another. And it’s the pace of this change that has most scientists worried- you rarely push things along this quickly in the geological record. 29

Thank you … Annual mean temperature changes across Australia since 1910. 30