While Australia debates how to reach our Paris Agreement targets, wider issues such as whether these targets are appropriate and how they might need to be adjusted in the future are receiving scant attention.

Australia’s current 2030 emissions reduction target is for a 26-28 percent reduction on 2005 levels. The Australian Labor Party has said that it would adopt a 2030 target of 45 percent below 2005 levels.  In the context of the global carbon budget, neither policy would see Australia doing a ‘fair share’.

The UN’s Intergovernmental Panel on Climate Change (IPCC) estimates the world has a remaining emissions budget this century of 1,040 GtCO₂-e to have mid-probability of meeting the Paris goals. Different approaches are taken on the question of how to divide these remaining emissions and related abatement tasks between countries. Key approaches include:

• population-based approaches, which divide up the emissions budget between countries based on their current and projected populations;
• cost sharing approaches, which consider and try to equalise economic impacts;
• historic responsibility approaches, which consider countries’ past emissions and responsibility for climate change; and
• hybrid approaches that combine population, cost and other measures of welfare.

If the remaining IPCC emissions budget was shared via a pure population approach, Australia would receive a share of 3,392 million tonnes. In 2015 Australia emitted 526 million tonnes, meaning at this rate our ‘fair share’ would be expended and Australia would need to have achieved net zero emissions in just over six years.

Using a modified population-based approach, which considers levels of development, the Climate Change Authority calculated Australia’s emissions budget as 10,100 million tonnes CO₂-e for 2013-2050. Australia’s current target of 26 percent reduction by 2030 would then require complete decarbonisation just five years later in 2035. Labor’s 45 percent target requires complete decarbonisation by 2040.

Under a cost sharing approach, the IPCC estimates that achieving the Paris targets would see global consumption 1.7 percent lower in 2030 compared to a no-action scenario. Modelling for the Australian government estimates that a 26 percent target would see Australian consumption just 0.6 percent lower, while a 45 percent target would see consumption 0.9 percent lower in 2030. Both policies would see Australia’s consumption grow, but experience reductions in growth of around half what is expected internationally.

Given Australia’s high historic emissions, high per capita emissions and high income, other approaches to assessing nations’ contributions to climate action all show that Australia’s climate targets are not doing a ‘fair share’. Any principle-based approach to target setting will result in highly developed, emissions-intensive nations like Australia having to pursue aggressive emissions reductions immediately and sustaining these reductions over the coming decades.

The small size of the remaining global emissions budget poses a significant challenge. All countries will need to ramp-up mitigation efforts. If the global community is to succeed in keeping emissions within the 2°C budget, mitigation efforts in Australia and elsewhere need to be significantly accelerated on timescales shorter than those contained in the Paris Agreement.