Transcript Document

One damn thing after another
cascading global change
Dr Bob Scholes
CSIR Fellow
UNISA
College of Economic and Management Science
25 November 2009
Have you noticed that everything
seems to be going wrong at once?
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Global financial crisis
Peak oil, fuel price hikes, energy crisis
in South Africa
Food price escalation, real hunger
affecting nearly a fifth of the world’s
population
Water shortages in many parts of the
world
The sixth extinction crisis….
What is going on???
© CSIR 2009
www.csir.co.za
Non-human factors
1. A globally-connected world
•Orbital forcing
•Solar activity
•Tectonics etc
Biogeochemical change
Climate change
•Atmospheric CO2
•Greenhouse gases
•N deposition
•Sediment transport
•P loading
•Temperature
•Rainfall
•Sea level rise
•winds
•Means and extremes
Land cover change
Biodiversity change
Marine resources
•Cropland expansion
•Degradation
•Deforestation
•Extinctions
•Domesticates
•Invasives
•Overfishing
•Pollution
•Habitat damage
Urbanisation
Economic development
Human development
•Coastal trend
•megacities
•Globalisation of trade
•Poverty alleviation
•Per capita consumption level
•Education
Technology development
•Fossil fuel based energy systems
•Tranport systems
•High-input agriculture
•Medical technology
Population
growth
2. The world is a complex, coupled humanecological system
• Bode’s Law
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When you suppress the high-frequency, small disturbances in a
system, the amplitude of the low-frequency events increases
Examples:
River canalisation often leads to bigger floods (hurricane Katrina)
Fire suppression leads to uncontrollable conflagrations (Victoria)
Financial securitisation instruments led to a meltdown (bank crisis)
• Overconnectivity
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As connectivity in systems exceeds a critical threshold, it becomes
much more likely that shocks will propagate through them
Examples:
Global pandemics: AIDS, SARS, H1N1
Global speculative bubbles and consequent deflation
WWF 2008 Africa : Ecological Footprint and Human Wellbeing WWF– Gland, Switzerland and
Global Footprint Network (GFN), Oakland, California USA.ISBN 978-2-88085-290-0
Human Development Index
Ecological footprint
Can developing countries rise to an
acceptable level of human development
without overloading the global
environment?
Adapting to a hotter, stormier future
Africa projections
2080-2099, 21 models, A1B scenario
Rainfall
Temperature
+20%
+2 ºC
+4ºC
-20%
Source:IPCC AR4 WG1 ch 11
Food supply in
southern
Africa
Fisher, G et al (2002)
Climate Change and
Agricultural Vulnerability
IIASA
Observations: Fires in forestry plantations in
southern Africa
Predicted wave run-up as a result of sea level rise and storm changes
Present storm
run-up line
Pot. future storm
run-up line
due to SLR
Pot. future storm
run-up line
due to SLR &
wave increase
Requirements for predicting coastlines include:
Improved understanding of interconnected coastal/physical
processes
(e.g. the interaction between sea-level rise and changing storm
intensities);
An accurate profile response model.
Adapt or mitigate?
Cost of
Impact and
Mitigation
Total cost curve
% of Global
GDP
5
Already Commitincurred
ted
1
1
2
3
4
5
6
(Global equilibrium temperature – preindustrial temperature) ºC
The effect of procrastination
Cost of
Impact and
Mitigation
Total cost curve
% of Global
GDP
5
Already
incurred
Committed
1
1
2
3
4
5
6
(Global equilibrium temperature – preindustrial temperature) ºC
Staying competitive in a low-carbon economy
Mind the gap!
Emissions from South Africa through 2050
Graphic: SA Long Term Mitigation Scenarios (2007)
Many mitigation options exist
Cost of mitigation (R/tCO2eq)
200
‘For free’ ‘Technology tweaks’
‘Fairy
godmother’
‘Market measures’
100
0
8
4
Mitigation achieved (billion tonnes CO2-eq)
% of gap between ‘Growth Without Constraints’ and ‘Required by Science’
-50
0
10
20
30
Two bridges are needed to close the gap
Emissions (billion tonnes CO2eq)
2
Growth without
constraints
1
Technical
bridge
Technical solutions Ethical
bridge
Required by science
0
2050
2003
Year
Persuading the world to take unified action
to keep global warming tolerable
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3 C mean global temperature rise is regarded as
‘dangerous climate change’
- We have already incurred 0.7  C and are committed to
~ 1  C more
- Staying below 3  C will require global emissions to
peak by ~ 2020, then decline to below half of 1990
levels by 2050
• If developed countries are to get room to increase
their emissions initially, developed countries need to
decrease theirs by 90%
Polar regions, small island states, Africa, the Amazon and
coral reefs suffer serious damage by that stage
If we aim at 3  C, there is a high chance we will actually
exceed it
© CSIR 2009
www.csir.co.za
[email protected]
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