Transcript Seasonal Outlook Briefing

Climate Change and its Effect on
Safety and Infrastructure
Dr David Jones
Head of Climate Analysis & Prediction
Bureau of Meteorology
Acknowledge: CSIRO, BoM, IPCC, ACE CRC, Dep
Climate Change
Overview
• Why you should care about climate change
• Recent Climate Changes (focus on Australia &
last 50 years):
• Human climate drivers - CO2 (the main GHG)
• Temperature
• Rainfall
• Sea level
• Looking to the future of climate change
Most of the observed increase in globally averaged
temperatures since the mid-20th century is very
likely due to the observed increase in anthropogenic
greenhouse gas concentrations (IPCC 2007)
Atmospheric CO2 and
Temperature
~390 ppm (or 450 e-ppm)
Greenland ~3M years
Antarctica ~13M years
400,000 years of data
The Human Drivers of Climate
Change
Methane stabilising, NOx
continuing to rise
CO2 rising rapidly
Climate Change Impacts –
Extremes, Safety and Infrastructure
• Direct effects of climate change on individual extreme
events: e.g., storms & heatwaves
• Indirect (background) effects: e.g., sea level rise
exacerbating floods, higher temperatures leading to drying of
forest fuels, lower fuel loads (due to winter drying)
• Effects on resilience & preparedness: e.g.,
– Rural depopulation due to drought  less fire fighting
volunteers?
– Uncertain return period for events (leading to over/under
investment in preparedness)
– Non-availability of insurance or insurance too expensive
– Uncertainty delaying or stopping investment decisions
– Long-term drought (or perceptions of fire risk) damaging
rural economies
Australian Temperatures
Annual and Decadal Mean Temperature Anomalies For Australia
Temperature Anomalies (°C)
1.25
1.00
Decadal mean
0.75
0.50
0.25
0.00
-0.25
-0.50
-0.75
-1.00
-1.25
1960
Departures from 1961-90 normal
1970
1980
1990
Year
2000
2010
Temperature has increased by about 0.7 C since 1960
2005 was Australia’s warmest year on record, 2009 the second
warmest
Changes in Maximum
Temperature Extremes
Number in Each Year
Distribution of High Maximum Temperatures
60
Decadal mean
50
40
30
20
10
0
1960
1970
1980
1990
2000
Year
Highest maximum temperatures tend to occur in recent years,
with the largest number on record in 2009
Melbourne: Mortality versus
Maximum Temperature
Black Saturday (46.4°C)
Vic Gov (Aged Care, 2010)
Nicholls (2010)
Australian Rainfall
Increase in many parts of northern and central areas
and decrease in the south and east
13 Years of Australian Rainfall
Recurring pattern of drought in the southwest and
southeast and floods in the north and centre
Victoria: Seasonal Fire Danger
13 year drought
Start of the long dry
Melbourne Airport 2008/09 – second worst fire
season on record. The big story is the drought.
Perth Dam Streamflows
338GL
177GL
82GL
Collapse of streamflow as a result of warming and drying
From: http://www.watercorporation.com.au/D/dams_streamflow.cfm
Change in Sea Level
Global Mean Sea Level (mm)
150
100
50
0
-50
-100
1860
1880
1900
1920
1940
Year
1960
1980
2000
2020
Approximately 20cm since 1870, with a steepening rise
Follows very closely global temperatures – a result of
thermal expansion and melting of ice
Change in Australian Sea Level
Since the early 1990s, sea level rise has been 1 to 3
cm/decade in the south and east and 7 to 10 cm/decade in
the north and west
Infrastructure and Safety
Gold Coast, QLD
Mandurah, WA
Waratah Bay, Vic
Some 711,000 addresses are
within 3 km of the coast and
within 6m of sea level
(Engineers Australia)
~3m
Impact in the Coastal Zone
Increase in the
frequency of high sea
level events for a 0.5M
sea level rise (ACE CRC
2008)
Managing our Coastal Zone in a Changing Climate (2009)
If sea-levels rose by 0.9 metres, 4700 residential lots
along the Lake Macquarie waterway foreshore would be inundated.
With almost 250,000 vulnerable coastal buildings,~3m
Queensland is at
the highest risk from all Australian states...
In Vic, more than 80,000 coastal buildings and infrastructure are at risk
from the projected sea level rise, coastal flooding and erosion.
Projections for Australia in
2030 (CSIRO & BoM)
Warmer by 0.4 to 2.0°C
 10-50% increase in days over 35°C
 10-80% decrease in days below 0°C
 Up to 10% less annual rainfall in SE Australia
 Up to 20% less annual rainfall in SW Australia
 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

The Future Rapid Warming
Expected
+1.7ºC
600ppm
+2.7ºC
850ppm
+3.2ºC
1250ppm
Warming will be largely dictated by CO2 emissions
Emerging Consensus on
Rainfall Changes
Rainfall change for 2090-2099 relative to 1980-1999.
Drying across southern Australia (and indeed most
subtropical areas).
How Will Changes Appear?
• In a country such as Australia where
natural climate variability is large, the
effects of climate change are more likely
to manifest themselves as a series of
threshold exceedences leading to
stressful events and dislocation followed
by (partial) recovery
• Climate change will manifest itself
through the weather
•
•
•
 Expect surprises
 Expect unexpected emergencies and impacts
 It is not easy (perhaps possible) to link individual events to
climate change until the climate change is large
In Summary
• Data from the Bureau, CSIRO and peer
organisations shows a picture of pervasive and
consistent trends
• The trends are continuing and will have an
escalating impact across society – health,
safety, infrastructure, planning…
• The quality of the data and science is high,
and the base data are all available for scrutiny
and independent analysis