Latest Projections of Climate Change & Impacts on Planning Systems

Transcription

1 Latest Projections of Climate Change & Impacts on Planning Systems Bryson C Bates CSIRO Climate Program

2 Presentation Outline Australia s hydroclimate & ecosystems are changing Climate change scenarios for 2030 Likely impacts of climate change Recent case studies Rainfall extremes Tropical cyclone occurrence Extreme sea levels Abrupt climate change Concluding remarks

3 Observed Changes in Australia Increase in max temp: C over last 90 years Increase in min temp: C over last 90 years Increase in hot days (+35 C): 5 days over past 50 years Increase in hot nights (+20 C): 9 nights over past 50 years Decrease in cold days (-15 C): 7 days over past 50 years Decrease in cold nights (-5 C): 8 nights over past 50 years Increase in Southern Ocean temp: +0.2 C over last 30 years Wetter NW Australia; drier S & E Australia Hotter droughts Increase proportion total rainfall from extreme rain-days in E Australia, decrease in SW Australia Tropical cyclones decreased frequency; increased intensity Sea-level rise: 10 cm over past 80 years 40% decline in October 1 st snow depths in past 40 years Jones et al (1997); Hennessy et al (1999); Gille (2002); Bergstrom (2003); Church et al (2004); Nichols (2005); Nichols & Collins (2005); Suppiah et al (2001); etc

4 Australia is Warming Temperature change ( o C) Australia s mean temperature since 1910 Eight climate models with additional GHGs in the atmosphere Climate models without additional GHGs in the atmosphere Karoly & Braganza (2004)

5 Inflow Perth Dams Murray R (E Aust): 01/06 driest-ever 5-year period

6 Warragamba Inflows Warragamba Catchment Rainfall mm Inflow ML 7 per. Mov. Avg. (Rainfall mm) 7 per. Mov. Avg. (Inflow ML) Inflow MLx Year Rainfall (mm)

7 Ecosystem Changes Encroachment of snow gums into subalpine grasslands at high elevations Increased penetration of feral animals into alpine & high sub-alpine areas Earlier arrival of migratory birds, range shifts & expansion of several bird species (beyond land cover changes) Change in genetic constitution of fruit fly (equivalent to 4º latitude shift) Eight mass coral bleaching events in GBR since 1979 (no known serious events prior to 1979)

8 Australia in 2030 Warmer by 0.4 to 2.0 o C 10-50% increase in days over 35 o C 10-80% decrease in days below 0 o C Up to 10% less annual rainfall in south-east and in spring in Queensland Up to 20% less annual rainfall in south-west Up to 10% more summer rainfall on east coast Up to 10% more autumn rainfall inland Heavier rainfall where average rainfall increases, or decreases slightly Increase in intensity of tropical cyclones Global sea-level rise (post-1990): 0.8 to 88 cm by 2100

9 Extreme Temperatures Days over 35 ºC: present vs 2030 City Present 2030 Adelaide to 16 Greater: heat stress Brisbane 3 6 energy demand for air conditioning Canberra 4 6 to 10 fire risk Hobart 1 2 water demand Less: Melbourne Perth to to 22 frost days energy demand for heating in winter Sydney 2 4

10 Likely Impacts Exacerbation of water availability problems in southern & eastern Aust [very likely] Alteration of structure, function & composition of many ecosystems [very likely] Increased vulnerability of coastal settlements to sea-level rise & storms [very likely] Reduced energy demand in water [likely] More heatwaves higher peaks in summer energy demand; mortality; risk of fires & black-outs [likely] Increased damage due to extreme weather events [likely]

11 Rainfall Extremes CSIRO Mark 3 AOGCM Θ A E IFD Statistical Downscaling DA CSIRO CCAM Nesting Structure Domain 1800km 1800km Resolution 22.5km Domain 600km 600km Resolution 7.5km

12 Value Added by Dynamical Downscaling 200 km 65 km 4 km fraction

13 IFD & DA Curves Point Scale Regional Scale Intensity (mm/h) Depth (mm) Duration (mins) Area (km 2)

14 Tropical Cyclone Occurrence Climate change projections Decrease or no change in total number of occurrences Increase in intensity (decrease in central pressure; increase in maximum wind speed)

15 Extreme Sea Levels Wave setup Wind Waves Storm Surge Highest Tide Mean Sea Level Lowest Tide Components: (1) storm surges, (2) tides & (3) mean sea-level rise

16 Current 1 in 100 Year Extreme Sea Levels Some inundation of these areas Rigby Island Fraser Island Flannagan Island Baines Swamp Big Swamp Boole Poole Peninsula Rota Mah Island Lake Reeve LAND Total area inundated = 25km 2

17 in 100 Year Extreme Sea Levels Mitchell River Tambo River Extensive inundation of these areas Round Head Jubilee Head Ocean Grange Lake Victoria LAND Total area inundated = 66km 2

18 Abrupt Climate Change?

19 Concluding Remarks Our climate has changed; is changing; & will change in the future The evidence is compelling recently observed changes faster than expected Cannot wait for full scientific certainty: It may never come; it may be too late! Challenge will get harder longer we wait Must take a balance of evidence approach for time being You don t have to believe in climate change; but you should manage the risk New scenarios due in 2007

20 Projections Probabilities People Perceptions 2 5 October 2007, Sydney Click to edit Master subtitle style For more information please contact: Paul Holper, CSIRO CLIMATE Phone: paul.holper@csiro.au