Download Science and decision-making

Science and
decision-making
Ian Lowe
21 May 2007
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Projected global warming
An example of non-linear change
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Millennium Assessment Report 2005
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Possible non-linear changes
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•
•
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North Atlantic circulation
Methane from Arctic tundra
Melting of [polar] ice
Drying of rainforests
Clearing and burning of
peatlands
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What is “dangerous” climate
change ?
• Two degrees of warming
might be dangerous
• Three degrees almost
certainly is
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How close is this ?
• Current CO2 380 ppm
• With other GHG, ~ 460 ppm CO2 equiv
• 510 ppm, 67 % chance warming > 20
• 590 ppm, 90 % chance warming > 20
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UK Government estimates
• 2003: 550 ppm, temperatures are
expected to rise between 2 and 5 0C
• 2006: “a limit closer to 450ppm or
even lower might be more
appropriate to meet a 20 C
stabilisation limit”
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“If emissions and concentrations grow
according to mid-range projections… the
cumulative warming by 2100 would be
approximately 3o to 5o C above preindustrial conditions… scientific evidence
suggests that changes of this magnitude
are likely to be associated with large
and perhaps abrupt changes in climatic
patterns … will adversely impact
agriculture, forestry, fisheries, availability
of fresh water, the geography of disease,
the liveability of human settlements…”
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Australia’s
Emissions (Mt)
1200
Business As
Usual
1000
Where we
are going
800
600
Kyoto target
400
What we
need to
achieve
200
0
1990
2000
2010
2020
Energy
Transport
Agriculture
Land clearing
2030
2040
2050
Fugitive, waste and
industrial processes)
Source: Adapted from the Australian Greenhouse
Lowe projections
Gas Inventory Ian
and ABARE
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It’s Achievable and Affordable
Real GDP
($b 2005)
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Source: The Allen Consulting Group (2006)
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S O C I E TY
ENVIRT
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ECONOMY
SOCIETY
ECOLOGY
Conclusion
• Even when the science is clear,
decision-makers will tend to
focus on the economy
• Science can inform and shape
the policy debate: CFCs, water ?
Forests ??
• Scientists need to be policy literate
• Policy-makers must be scienceliterate
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Photo: NASA
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