Australia’s carbon budget – 10.1 billion tonnes by 2050

The Climate Change Authority has recommended a “carbon budget” of 10.1 billion tonnes of CO2 equivalent for the 37 years from 2013-2050, but notes this would be exhausted within 17 years at current rates of emissions.

The carbon budget is constructed as part of what the CCA estimates is Australia’s “fair share” of action to reach the global goal of limiting average global warming to 2C. Other private estimates have suggested a budget that could be exhausted within a decade.

The CCA says a carbon budget is important, because keeping a clearly inadequate target of 5 per cent reductions by 2020 would require an “implausibly rapid acceleration” of effort beyond 2020.

“If Australia adopted it and still wished to meet its fair share of the 2 degree budget, it would need to reduce emissions by a further 45 percentage points in the decade to 2030, and then would have only 14 per cent of its budget left for the next two decades.

“A 2020 target of not less than 15 per cent would keep Australia’s future options open, including the option of Australians doing their fair share of the strong global action that is in the national interest.”

“A 5 per cent target for 2020 cannot credibly be described as a ‘gradual start’ to meeting Australia’s 2 degree budget,” the CCA writes.

“A 5 per cent target would leave such large reductions for later that future Australians would either face a very large emissions reduction task or have to abandon the long term national emissions budget. This is inequitable in the first case and against Australia’s national interest in the second.”

However, Australia’s carbon budget might need to be even tougher. There is huge debate among international governments about what defines a “fair share” of the global budget. The CCA canvasses a range of options (see graph below), but the most dramatic impact on Australia’s budget would be based on Australia’s share of the global population.

The CCA said its view is that eventual equality in per person emissions is fair.  But it concedes that that is not likely to happen soon. After all, hat would reduce the budget by a third, suggesting that Australia could exhaust its budget in just 6 years on current levels. “That is just not going to happen,” noted CCA chief executive Anthea Harris.