sis climate change the latest news holper 2007
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Scientists in Schools Program - Presentations from the Energy and Climate Change SymposiumTRANSCRIPT
Climate change – the latest news
Paul HolperCSIRO Marine and Atmospheric ResearchScientists in Schools, Newcastle, 25 October 2007
Sunday Age, 28 M
ay 2006
Outline
• Climate change – the basics• The latest science
• IPCC Fourth Assessment Report• Climate change in Australia• Impacts of climate change• What to do
The greenhouse effect
Cape Grim Baseline Station
Atmospheric carbon dioxide concentrations
Carbon dioxide concentrations are now greater than at any time during the past 650,000 years.
Svante Arrhenius – “On the influence of carbonic acid in the air …”
Svante August Arrhenius b. February 19, 1859, Wijk, Sweden
d. October 2, 1927, Stockholm, Sweden
“Doubling CO2 leads to increase of ~5°C”
Carbon dioxide and temperature last 420, 000 years
100
150
200
250
300
350
0100,000200,000300,000400,000years before present
CO
2 (pp
m)
-10
0
10
20
tem
pera
ture
(o C)
Longer-term changes
Average Australian surface temperature
Australian annual mean temperatures have increased by approximately 0.9°C since 1910
IPCC 2007: Observed changes
• Rises in global average air and ocean temperatures
• 0.7ºC increase over past 100 years in surface air temp.
• Eleven of the last 12 years are the warmest since 1850
• Mountain glaciers and snow cover have declined in both hemispheres
• Annual average Arctic sea ice extent has shrunk • Increased drying due to higher temperatures and
decreased rainfall has contributed to more intense and longer droughts since the 1970s
• Frequency of heavy rainfall events has increased • Hot days and nights and heatwaves have become
more frequent. Cold days and nights and frosts have become rarer.
Decrease in snow, permafrost glaciers & sea ice
Source: w
ww
.ncar.ucar.edu/eo/kids/green/warm
ing6.htm/nsidc.org/data/g00472.htm
lMuir Glacier, Alaska, August 13, 1941 Muir Glacier August 31, 2004William O. Field Bruce F. Molnia (USGS).
Arctic changes, 1861 - 2100
Arctic sea ice
International findings: IPCC 2007
• Warming of the climate system is unequivocal.
• Very likely that anthropogenic greenhouse gas emissions caused most of the warming since the 1950s (>90% confidence)
• Likely that greenhouse gases alonewould have caused more warming than observed as volcanic eruptions and aerosols have offset some of this warming
CO2 concentrations, stabilisation and future temperature
Even if CO2 concentrations are stabilised, temperature and sea level will continue rising
CO2 growth rate rising
Rahmstorf et al.Growth rate has risen from <1% pa in the 1900s to > 2.5% pa from 2000 to 2005.
Tracking at high end of IPCC temp. projections
Rahmstorf et al.
Rahmstorf et al.
Tracking at very high end of sea level rise projections
Earth at night
Fuel use
Country size represents proportion of global fuel use.www.worldmapper.com
Climate change in Australia
CSIRO-Bureau of Meteorology (2007)Australian Climate Change Science Program Australian Greenhouse Office, DEWR
• The most comprehensive report on climate change for Australia
• Detailed 148 page technical report with 291 scientific references. Over 50 authors, contributors, reviewers and editors.
• 8-page brochure, impacts brochure, CD
www.climatechangeinaustralia.gov.au
Projected warming in 2030: 50 percentile, A1B
A1B mid-range scenario, best estimate projected warming 2.8ºC by 2100
ºC
Projected warming in 2030: Model range
10 percentile, A1B 90 percentile, A1B
Projected warming in 2030: Model range, A1B
A1B mid-range scenario, best estimate projected warming 2.8ºC by 2100
Chance of at least a 1, 2, 3 or 4°C warming
New South Wales temp. change 50th percentile annual
Temperature projections to 2100
Stippling indicating where decrease is ‘likely’ (more than 67% probability of decrease)
No areas show ‘likely’ increase
Projected rainfall change 2030: 50 percentile, A1B
A1B mid-range scenario, best estimate projected warming 2.8ºC by 2100
Comprehensive projections: other variables
• Wind speed mainly increases• Relative humidity small decreases• Solar radiation increases in the south• Potential evaporation increases• Sea surface temperature increases, especially Tasman sea
Impacts of climate change
Australia is already experiencing impacts from recent climate change
• increasing stresses on water supply and agriculture, changed natural ecosystems and reduced seasonal snow cover
Ongoing vulnerability to extreme events• substantial economic losses caused by
droughts, floods, fire, tropical cyclones and hailMore heat waves, fires, floods, droughts and storm
surges. More intense cyclones and hail storms.Water security problems to intensify by 2030 in
southern and eastern AustraliaSignificant loss of biodiversity to occur by 2020 at sites
including the Great Barrier Reef and Queensland Wet Tropics
Increased risks to major infrastructure
What to do?
• Adaptation (‘climate-proofing’) • maximising opportunities and minimising threats from current and
likely future climatic changes, particularly in vulnerable areas
• Mitigation (reducing greenhouse gas emissions or enhancing sinks)
• reducing the risk of larger and dangerous changes in climate andassociated impacts to which we cannot adapt
Big solutions!
Deploy 16 trillion sunlight-refracting shades. Each mirror would span less than a square metre and block 2% of sunlight.
Conclusions
• Climate change is real and underway• Most of the warming of the past 50 years is due to human activities• Climate change will continue in the 21st century• Detailed information on climate change in Australia is now
available• Great value in understanding likely impacts to reduce damage and
increase benefits (adaptation)• Slowing climate change will require large and global reductions in
emissions (mitigation)
Thank you
CSIRO Marine and Atmospheric ResearchPresenter’s namePresenter’s title
Phone: +61 3 9545 2176Email: [email protected]: www.cmar.csiro.au
CSIRO Marine and Atmospheric ResearchPresenter’s namePresenter’s title
Phone: +61 3 9545 2176Email: [email protected]: www.cmar.csiro.au/group
Contact UsPhone: 1300 363 400 or +61 3 9545 2176
Email: [email protected] Web: www.csiro.au
CSIRO Marine and Atmospheric ResearchPaul Holper
Phone: +61 3 9239 4661Email: [email protected]: www.csiro.au