Transcript Climate change and population

CLIMATE CHANGE
& POPULATION
Ian Lowe
GEO4: “Unprecedented environmental
change at global and regional levels”
• Increasing global average temperatures,
widespread melting of snow and ice,
rising global average sea level
• Unsustainable land use and climate
change driving land degradation
• Aquatic ecosystems heavily exploited
• Water availability declining globally
• Almost all well-studied species declining
in distribution, abundance or both
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Earth is overheating
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Earth is overheating
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Global warming is affecting Australia today
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Global Temperature Change
1980s: warmest decade ever
1990s: even warmer. Every
year above 1980s average
2000s: warmer yet. Every
year above 1990s average.
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To have a better than even chance of
keeping global average temperature
rise below 2°C, the world would need
to be emitting less than half the 2000
amount of CO2 by 2050.
So global emissions need to peak by
2020 and then decline rapidly.
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The window for action is rapidly closing
‘Cumulative emissions of carbon dioxide largely determine global
mean surface warming by the late 21st century and beyond’
Amount
Remaining:
275
Total Carbon
Budget:
790
GtC
GtC
Amount Used
1870-2011:
515
GtC
AR5 WGI SPM
65% of our carbon budget compatible with a 2°C goal already used
IPCC AR5 Synthesis Report
Australia’s
Emissions
(Mt)
1200
1000
Where we
are going
Business As
Usual
800
600
What we
need to
achieve
Kyoto target
400
200
0
1990
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2010
2020
Energy
Transport
Agriculture
Land clearing
2030
2040
Fugitive, waste and
industrial processes)
Source: Adapted from the Australian Greenhouse
Gas Inventory and ABARE projections
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2050
13
Current strategy
• Billions for public subsidies of fossil
fuel use [car production & use,
aviation, road freight, aluminium…]
• Export of fossil fuels on huge scale
[with further expansion plans]
• Large costs of climate change
[drought, cyclones, bushfires, water…]
• Little serious spending on solutions
• superficial talk of nuclear power or
“clean coal”
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IEA World Energy Outlook 2008
“nothing short
of an energy
revolution”
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Sustainable energy future
• Improve efficiency of turning energy
into services [transport, cooling,
lighting, motive power etc]
• Phase out supply technologies
based on problematic resources
• Eliminate technologies imposing
unacceptable environmental costs
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Overseas trends
• Solar is now the cheapest power
in the USA: 3.87 c / kWh
• Renewables half of all new power
installed globally in 2014
• ~ 30% power now from renewables
• Gas replacing coal
• Total coal use declining
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Cost of new power
(Bloomberg New Energy Finance 7/15)
•
•
•
•
Wind farm
Baseload gas
Large scale solar
New coal-fired
$74 / MWh
92
105
119
• “Wind is already the cheapest… solar PV
will be cheaper than gas in 2017”
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Renewables can’t supply our needs ?
• Wind power supplied over 50 %
of total power consumption of
South Australia for August 2014
• On one September day it met
100 % of demand [& exported]
• Ellison, McGill & Diesendorf: all
power needs now can be met
from a mix of renewables
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Population Impact
• SoE 1 (1996): cause of problems
• Australia’s Kyoto argument
• ACF EPBC Act submission
• Environmental impact I = P. A. T , so
proportional to P unless Affluence
declines or Technology improves
faster than population grows
The numbers are:
• “natural increase” ~ 150,000 per year
• Birthrate ~ 1.9 per adult woman, but
number adult women increasing
• Net migration ~ 250,000 per year
• Refugee quota ~ 20,000
• Population growing > 1 million every
3 yrs
• Would be growing 1 million every 7
yrs if zero net migration now
Projections
• Population stabilises in 2030s at
~ 28 million if zero net migration
• Stabilises later at higher level with
net migration < 70,000
• At current migration rates and
birthrate, 2050 population > 40
million, 2100 > 60 million