The Physics of Climate Change Graeme I Pearman GP Consulting Pty Ltd Monash University.

The Physics of Climate Change

Graeme I PearmanGP Consulting Pty Ltd

Monash University

February 09, 2007 Physics Teachers’ Conference, Monash


• The IPCC

• The gases and other drivers of change

• Observed changes

• Projecting future change globally

• Projecting future change in Australia

• Managing risk and uncertainty

• Energy futures

• Conclusions

United Nations Framework Convention on Climate

Change (UNFCCC)Over archingIn force (1992)Australia signed

The Kyoto ProtocolDeveloped world targetsIn force (2005)Australia not signed

The Intergovernmental Panel on Climate Change (IPCC)

Technical UnderpinningAustralian scientists involved

Emission reductions or minimisation

Asia Pacific Partnership on Clean Development & ClimateTo promote clean energy technology with the involvement of governments, business and research institutesDoes not set binding greenhouse emissions reduction targetsCountries involved – Australia, US, Japan, China, India and South Korea - account for nearly 50% of greenhouse gas emissions from 2006

United Nations Framework Convention on Climate

Change (UNFCCC)Over archingIn force (1992)Australia signed

The Kyoto ProtocolDeveloped world targetsIn force (2005)Australia not signed

The Intergovernmental Panel on Climate Change (IPCC)

Technical UnderpinningAustralian scientists involved

Emission reductions or minimisation

Asia Pacific Partnership on Clean Development & ClimateTo promote clean energy technology with the involvement of governments, business and research institutesDoes not set binding greenhouse emissions reduction targetsCountries involved – Australia, US, Japan, China, India and South Korea - account for nearly 50% of greenhouse gas emissions from 2006

IPCC Fourth Assessment Reportwww.abc.net.au/news/opinion/items/200702/s1838077



• The IPCC

• Gases and other drivers of change• Observed changes• Projecting future change globally• Projecting future change in Australia• Managing risk and uncertainty• Energy futures• Conclusions


Changes in greenhouse gases

Source, IPCC 4AR, SPM, 2007

Other gases with greenhouse potential

Source, IPCC 4AR, SPM, 2007


Relative contribution to warming

Concentration Change per year

Radiative forcing Wm-2

<1700 2005

Carbon dioxide 275-285 379 ppmv 1.9 ppmv +1.66 ±0.17

Methane 715 1774 ppbv ~nil +0.48 ±0.05

Nitrous oxide 270 319 ppbv 0.83 ppbv +0.16 ±0.02

CFCs HCFCs Chlorocarbons

NA NA Slightly negative

+0.32 ±0.03

Ozone - stratosphere

- Troposphere

-0.05 ±0.10

+0.35 ±0.30

HFC, PFC, SF6 NA NA 10% +0.017 ±0.002

Total +2.63 ±0.26


Lifetime and global warming potentials of selected greenhouse gases

Gas Symbol Lifetime Years

Global Warming Potential

20-years 100-years

Carbon dioxide CO2 ~80 1 1

Methane CH4 12 72 25

Nitrous oxide N2O 114 289 298

CFC-11 CCl3F 45 3800 4750

CFC-12 CCl2F2 100 8100 10900

HFC-23 CHF3 270 11700 14800

Sulphur hexafluoride SF6 3200 23900 16300

IPCC 4AR, Chapter 2, 2007

Radiative forcing of

climate between 1750 and

2005

Chapter 2, IPCC 4AR



• The IPCC• The gases and other drivers of change

• Observed changes• Projecting future change globally• Projecting future change in Australia• Managing risk and uncertainty• Energy futures• Conclusions

Changes of global

temperature and northern hemisphere snow cover

Source: IPPC 4AR, SPM

North Australian tropics annual sea surface temperature anomaly

(from1961-1990)http://www.bom.gov.au/cgi-bin/silo/reg/cli_chg/timeseries.cgi


Key Findings: Observed change

• Global mean temperatures have risen over past 100 years by 0.74 ±0.18

• Rate of warming in last 50 years ~ double that of the last 100 (0.13 ± 0.03)

• Warmest years 1998, 2005, 2002, 2004

• 11 of last 12 years rank amongst the 12 warmest years on record

• Land warming faster than over the oceans


Key Findings: Observed change

• Precipitation generally increased over land north of 30oN from 1900-2005 and decreased in the tropics since 1970s

• Substantial increase in heavy precipitation events

• More common droughts, especially in tropics and subtropics since 1970

• Tropospheric water increasing• “Global dimming” is neither global in

extent nor has it continued after 1990

The Earth is de-glaciating


Key Findings: Observations

• Snow cover has decreased in most regions, especially in spring and summer

• Freeze-up and break-up dates for river and lake ice (variable). For the NH:– Feeze-up later by 5.8 ±1.6 days per century– Break-up earlier at a rate of 6.5 ±1.2 days per

century

• Arctic sea-ice extent decline of 2.7 ±0.6 per cent per decade

50

40

30

20

10

0

Se

a le

ve

l, c

m

1850 1900 1950 2000 2050 2100

After J Church, personal communication


Key Findings: Observations

• Sea levels have rise at a rate of:– 1961-2003 1.9 ± 0.5 mm yr-1– 1900-2000 1.7 ± 0.5 mm yr-1

– 1993-2003 1.6 ± 0.5 mm yr-1 thermal expansion

2.8 ± 0.7 mm yr-1

deglaciation

• Ocean acidification– 0.1 pH unit so far

Greenland Mass Loss – From Gravity Satellite

Major Key MessagesGases• Current carbon dioxide and methane

concentrations far exceed those of last 650,000 years

• Increases primarily due to fossil fuel use, agriculture and land-use changes

Warming• Unequivocal, evident in air and ocean

temperatures, melting of snow and ice and rising sea-levels

• Warming an effect of human activities - at least 5 times greater than that due to solar output change



• The IPCC• The gases and other drivers of change• Observed changes

• Projecting future change globally• Projecting future change in Australia• Managing risk and uncertainty• Energy futures• Conclusions


ε is the emissivity (“blackness”, for the Earth~1.0), σ the Stefan-Boltzmann (Law) constant (5.67 x 10-8 W m-2 K-4), T is the temperature (oK), α is the reflectivity of the Earth (~0.3), r is

the radius of the planet

Distance from sun Min.-Max. (106 km)

Surface pressure (Relative to Earth)

Main greenhouse

gases

Surface temperature, absence of

Greenhouse Effect (oC)

Observed surface

temperature

(oC)

Warming due to green-house

effect (oC)

Venus 107-109 90 >90% CO2 -46 477 523

Earth 147-152 1 ~0.04% CO2 ~1% H2O

-18 15 33

Mars 207-249 0.007 >80% CO2 -57 -47 10

πr2(1-α)S = 4r2εσT4

Greenhouse effect of neighbouring planets


Key components/processes of the climate system

• Radiation budget

• Hydrologic cycle

• Fluid dynamics



• Radiation budget– Incoming solar radiation– Planetary movements– Cloud reflection– Aerosol/dust reflection– Surface reflection and absorption

• Hydrologic cycle• Fluid dynamics

Science behind the model



• Radiation budget• Hydrologic cycle

– Evaporation– Cloud formation– Precipitation– Interception– Runoff

• Fluid dynamics



• Radiation budget• Hydrologic cycle• Fluid dynamics

– Pressure fields– Circulation of air vertically and horizontally-

winds– Circulation of water vertically and

horizontally- currents– Coriolis forces, planetary vorticity


What is a climate model?

• Complex, lengthy computer program

• Incorporating all physical/chemical and biological processes that drive weather and climate

• Reproducing the way in which climate behaves from day to day, and season to season


Climate models have greatly improved

Modelled tropical cyclone

Global warming relative to 1980-199917-model average, 4 emission futures

Watterson and Arblaster (2005)

2.3oC

1.9oC

3.2oC

2.4oC

Annual warming for 2080-209917-model average, A1b emission futures

Watterson and Arblaster (2005)

Key Findings: Future warmingBased on up to 23 global climate models

• Mean temperatures– 2025 0.6-0.7 oC Higher over land/high latitude– 2055 1.3-1.7 oC– 2095 1.7-4.0 oC

– Transient at time of doubling CO2 2-4.5 oC

• Extreme temperatures– More frequent, intense, longer lived heat waves– Minimum temperatures warm faster than maximum– Decrease in frost days Mid to high latitudes– Increased growing season Mid to high latitudes

Key Findings: Precipitation

• Mean precipitation– Increase tropics (monsoon)/high latitudes– Decrease subtropics/mid latitudes

• Extreme precipitation– Intensity of events to increase– Longer periods between events (sub-tropics/mid

latitudes)

• Tropical cyclones (hurricanes, typhoons)– Increased peak wind and precipitation– Possible overall less frequent– Geographic shifts

• Mid latitude storms– Fewer- pole ward shift (several degrees)– Lower central pressure- increased wind speed/ waves

June-July-August

Key Findings

• El Nino– To continue- still confused trends if any

• Monsoons– Increase precipitation but projections confused by

aerosols• Snow and ice

– Snow cover and sea ice extent decrease– Glaciers and ice caps lose mass– Loss of Arctic sea ice as early as mid 21st century– Increase of thaw depth

• Carbon cycle– Unanimous agreement: loss of CO2 absorption

efficiency– Greater atmospheric accumulation of CO2

– Still significant model difference/uncertainties

Net uptake: Oceanic 2.3 GtC yr-1

Terrestrial 0.2 GtC yr-1

Partitioning fossil CO2

-20

-16

-12

-8

-4

0

0 1 2 3 4 5 6CO2 (GtC yr-1)

(O

2/N

2)

(per

meg

yr

-1)

Fossil FuelAtmosphere

OceanTerrestrial

-250

-200

-150

-100

-50

0

50

100

150

200

Year

0 2

/N2)

(per

meg

)

77 79 81 83 85 87 89 91 93 95 97

Cape Grim O2/N2

air archive13C-predicted curveSIO flasks

URI CSIRO South Pole firn

-8

-7.9

-7.8

-7.7

-7.6

-7.5

-7.4

-7.3

-7.2

C

(p

er

mil

PD

B) Cape Grim 13C in CO2

in-situ CO2 extractionair archive

325

330

335

340

345

350

355

360

365

CO

2 (

ppm

)Cape Grim in-situ CO2

Key Findings: The oceans

• Sea level– By end of century from end of 21C, 0.19-0.58 m– Regionally different– Limited knowledge of ice flows and sea level

contribution

• Ocean acidification– 0.1 pH unit so far– 0.14-0.35 pH units in 21C– Southern Ocean exhibits under-saturation

• Atlantic ocean overturning – decrease by less than 0-25% no collapse by 2100


Major key messagesCause of warming• Very likely (>90%) greenhouse-gas increase

caused most of warming since mid-20th century• Extremely unlikely (<5%) warming caused by

natural variability

Future warming• Warming for next 2 decades to be 0.2oC/decade• BAU emissions would very likely (>90%) to

cause 20st century warming larger than during 20th century



• The IPCC process• The gases and other drivers of change• Observed changes• Projecting future change globally

• Projecting future change in Australia• Managing risk and uncertainty• Energy futures• Conclusions

Annual Rainfall: ((1976-2003)/(1925-1975))x100

Data from P.Hope, Bureau of Meteorology, Melbourne

Natural system changes linked to climate change in Australia/New Zealand

• Ecosystems– Semi arid woodlands, Eucalypt savannas, rain

forest/woodland, subalpine, mangroves, coral reefs

• Genera– birds, Antarctic beech, mammals, insects (including

genetic changes), sea urchins, marine mammals, fish, invasive species

• Behaviour – flowering phenology, earlier migration and egg

laying, seed production

Lough (2000); Evans et al. (2003): Hughes (2003); Thresher et al. (2003); Chambers et al. (2005); Umina et al. (2005); etc.

Key Findings: Australian Region• Mean temperature

– South of 30oS by 2100 2.6 (2.4-2.9 inter-quart range)

– North of 30oS by 2100 3.0 (2.8-3.5)– Less in coastal regions more inland

• Mean precipitation– South of 30oS, JJA, 2100, -26 to -7%– East coast increase in summer, decrease in winter. Less

robust

• Snow cover– 30-days snow cover reduced to14-54% by 2020 and 30-

93% by 2050

• Potential evaporation– Almost all indications are for a moisture balance deficit-

a drier Australian environment

Key Findings:Australian Region- Extremes

• Days over 35oC – Melbourne 8 to 9-12 (2020) and 10-20 (2070)– Perth 15 to 16-22 (2020) and 18-39

• Commonly return period of extreme rainfall events halve through 21st century

• NSW/Qld rainfall 30% increase in magnitude, 1 in 40 becoming 1 in 15 year event

• Marked increase frequency of rainfall deficits, doubling in some case by 2050

15-model average

changes in temperature

by 2070, relative to

1990

Suppiah et al. (in prep)

2070 Mid

(b)

Annual

Summer

Winter

Autumn

Spring

Temperature change oC

15-model average changes in rainfall by 2030 relative to 1990

Mid refers to middle range global warming values used to scale the patterns of change

Suppiah et al. (in prep)

Mid

Annual

Summer

Winter

Autumn

Spring

Rainfall change (%)

Vulnerable Drivers of change

Impacts Economy

EasternAustralianAlps

Reduced precipitation & snow cover

Shortened winter season. Loss of plant species, increased shrubs, less herbs

Threats to built environment, biodiversity, ski industry viability/costs and tourism

EasternQueensland

Coastal impacts of sea level rise, storm intensity

Losses to infrastructure and coastal amenity

Tourism implications. Infrastructure costs and insurance risk

Kakadu Salt water intrusions

Displacement of freshwater wetlands with mangroves

Biodiversity and tourism implications

MurrayDarlingBasin

Reduced river flow Enhanced water competition for natural flows, irrigation and town water supplies

Higher cost of water. Loss of agricultural production and biodiversity

Queenslandwet tropics

Coastal impacts of sea-level rise & storm Intensity

Species extinction, loss of coral reefs, coastal flooding and infrastructure damage

Tourism implications. Infrastructure costs & insurance risk

SW WesternAustralia

Drying Water shortages, fragmentation of ecosystems

Loss of agriculture production or enforced changes. Loss of biodiversity

SubAntarcticaislands

Warming & de-glaciation

Loss of key species and rapid changes to ecosystem assemblages

Loss of biodiversity

Potentially vulnerable systems



• The IPCC processThe IPCC process• The gases and other drivers of changeThe gases and other drivers of change• Observed changesObserved changes• Projecting future change globallyProjecting future change globally• Projecting future change in AustraliaProjecting future change in Australia

• Managing risk and uncertaintyManaging risk and uncertainty• Energy futuresEnergy futures• ConclusionsConclusions

Exposure Sensitivity

Adaptivecapacity

Potentialimpact

Vulnerability

Probability Magnitude

RiskStrategy

Mitigate

Managed adaptation

ResilienceModified from Allen Consulting Group (2005)

“This is not just an environmental problem. It is a defence problem. It is a problem for those who deal with economics and development, conflict prevention, agriculture, finance, housing, transport … trade and health”.

UK Foreign Secretary, Margaret Beckett, The Age, Oct. 26, 2006



• The IPCC process• The gases and other drivers of change• Observed changes• Projecting future change globally• Projecting future change in Australia• Managing risk and uncertainty

• Energy futures• Conclusions

A “wedges” approach to energy futures and climate change

Conventional Biomass

Energy Efficiency & Reduced Demand

Solar

Wind

Advanced Nuclear

Advanced Gas

Advanced Coal

Adapted from Battelle: similar approach used by Princeton University, see Socolow et al. Environment , 46 (2004)

Carbon capture and sequestration

National anthropogenic emissions of greenhouse gases

Mt CO2 equivalent (excluding forestry/land-use change), 2004

Australia 528Canada 758France 562Italy 582Netherlands 218Poland 388Spain 427Ukraine 413United Kingdom665United States 6067

http://unfccc.int/resource/docs/2006/sbi/eng/26.pdf



• The IPCC process• The gases and other drivers of change• Observed changes• Projecting future change globally• Projecting future change in Australia• Managing risk and uncertainty• Energy futures

• Conclusions

Conclusions

• We are challenged by– The complexity, need for integrated responses– Self interest, balancing competing aspirations– A spectrum of uncertainty

• The changes are large, even on long time scales• They demand immediate and on-going action• There is no guarantee that we can/will respond in

time to avoid serious repercussions• This is not doom-saying but a message from

mainstream climate science

Sponsor Address Content

Aust. Acad. of Science

http://www.science.org.au/nova/ Carbon accounting, climate and health, biodiversity, health, etc.

Australian Bureau of Meteorology

http://www.bom.gov.au/climate/ Information about climate

http://www.bom.gov.au/cgi-bin/silo/reg/cli_chg/trendmaps.cgi Trends maps for Australia’s climat

http://www.greenhouse.gov.au/ Q and A, carbon accounting, energy

Australian Greenhouse Office

http://www.greenhouse.gov.au/ Q and A, carbon accounting, energy, etc

http://www.greenhouse.gov.au/inventory/2003/pubs/inventory2003.pdf Emission inventory

http://www.greenhouse.gov.au/education/tips.html What you can do

Hadley Centre, British Meteorological Office

http://www.metoffice.com/research/hadleycentre/pubs/brochures/ Publications

http://www.metoffice.com/research/hadleycentre/models/modeldata.html Climate predictions

http://www.metoffice.com/research/hadleycentre/obsdata/globaltemperature.html Global temperatures

CRC G/H Accoun.

http://www.greenhouse.crc.org.au/about%5Fgreenhouse/ Greenhosue, carbon accounting, impacts, etc.

CSIRO Marine and Atmospheric Research

http://www.cmar.csiro.au/e-print/open/gh_faq.htm#gh1 Greenhouse questions and answers

http://www.dar.csiro.au/capegrim/ghgasgraphs.html Greenhouse-gas levels, Cape Grim

http://www.dar.csiro.au/publications/projections2001.pdf Climate projections

Environment Canada

http://www.msc.ec.gc.ca/education/scienceofclimatechange/understanding/FAQ/FAQ-finalenglish.pdf

Greenhouse questions and answers

NOAA http://www.ncdc.noaa.gov/oa/climate/research/anomalies/anomalies.html Global data

Princeton University

http://www.princeton.edu/~cmi/resources/CMI_Resources_new_files/Environ_08-21a.pdf

Wedges approach to future energy options

Roy. Soc. London

http://www.royalsoc.ac.uk/downloaddoc.asp?id=1630 Facts and fiction about climate change

Concerned Scientists

http://www.ucsusa.org/global_warming/science/global-warming-faq.html Frequently asked questions

Vict. Government http://www.greenhouse.vic.gov.au/ Victorian greenhouse strategy, etc.

United Nations http://unfccc.int/2860.php Framework Convention on Climate Chnage

http://www.ipcc.ch/ Recent Fourth Assessment Report

http://www.dar.csiro.au/publications/projections2001.pdf

The Physics of Climate Change Graeme I Pearman GP Consulting Pty Ltd Monash University.

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