Conclusion - Four Degrees of Global Warming - page 231

The global average per capita allocation, based on projected 2050 global
population data and a budget of 500 billion tonnes CO 2 -e divided by approxi-
mately 9 billion (roughly the UN's median projection), is 55.6 tonnes per
capita for a 50 per cent chance of staying below the 2°C limit. For a global
budget of 330 GtCO 2 -e (67 per cent chance), it is 36.7 tonnes per capita, and
for a global budget of 330 GtCO 2 -e, (75 per cent chance) it is 20 tonnes per
capita.
These outcomes translate into an Australian national carbon budget (meaning
all the carbon we have left to emit) of 1.72 billion tonnes, or 1.13 billion tonnes,
or 620 million tonnes, depending on the level of risk we adopt in relation to
the 2°C limit. In other words, even before taking equity considerations (i.e.
responsibility, wealth and capacity) into account, Australia's carbon budget will
provide for only between one and three more years of emissions at its current
annual emissions level.
Australia's 'ambition gap'
As noted earlier, current aggregated national mitigation pledges for 2020 fall
well short of what is required to hold to that 2°C 'guardrail', much less a safer
target of 1.5°C. This deficit in international effort is now commonly called the
'ambition gap'. The UNEP 2012 Emissions Gap report estimated the gap between
current mitigation pledges and effort and the emissions level consistent with a
'likely' (greater than 66 per cent) chance of staying within the 2°C target, to be
14 billion tonnes per annum CO 2 -e in 2020 (Höhne et al., 2012: 30).
Clearly, more is required of all parties to reduce emissions rapidly by that
amount. At minimum, major emitters need to adopt a proportionate, science-
based 'carbon budget' response to bridging the ambition gap of 14 billion tonnes
per annum by 2020. Australia too will need to accept a proportion of this
additional reduction. A minimally equitable approach would be to adopt further
reductions proportionate to Australia's global emissions contribution, or 1.3 per
cent of the 'outstanding' 14 billion tonnes. 4 This would add some 182 million
tonnes to Australia's 2020 mitigation target of 2 27.8 million tonnes below its
2000 baseline or, put another way, require an increase of another 2 33 per cent
to its present target of 2 5 per cent of total emissions by 2020, to at least 2 38 per
cent below 2000 levels by 2020.
Wealth and economic capacity
Australia's comparative wealth, capacity and economic advantage - derived
in part from its historical use of fossil fuels - need to be taken into account in
determining a short term target that reflects the requirements of Article 3.1 of
the UNFCCC and better enables Australia to participate in the international
climate framework on the basis of equity and in accordance with its common but
differentiated responsibilities and respective capabilities.
Australia is the world's 12th largest economy by aggregate Gross Domestic
Product (GDP) and also by GDP per capita. It is second among nations on the