This week, fires ignited across the state. The Coolagolite blaze in Bega Valley burned 6,700ha of land. We want to share with you some background on the fire data we’ve collected so far, and what we hope to do. You can find it at the end of this email. This week, we’re going back to a big picture climate data topic: carbon budgets.
Why bother to budget?
Everyone understands a basic budget. You have a clear and limited resource that gets spent over time.
In carbon budgets, the starting point is temperature. How hot are we willing to get? That number is set by humans.
The currency is carbon. How much can we emit while staying below the temperature target? That number is set by nature.
Global carbon budget
Humanity has agreed that warming must be limited to ‘well below 2°C’ above pre-industrial levels (and we should try to limit it to 1.5°C). That was the Paris Agreement.
The IPCC estimates that for a 67% chance of staying below 2°C, the world’s total emissions for the 200 years between 1850-2050 must be less than 3550 GtCO2.*
For a 50% chance of staying below 1.5°C, emissions must be less than 2900 GtCO2.*
Current total emissions are 2475 GtCO2, according to the Global Carbon Project. In 2021, the world emitted 41.1 Gt CO2.
If that yearly pace continues, the 2050 budget would be exhausted in 2033 (for 1.5°C) and 2049 (for 2°C).
Australia’s carbon budget
Australia’s Climate Change Authority used the global budget to calculate Australia’s ‘fair share’ of carbon emissions.
It says Australia gets 0.97% of the total budget. Not bad, seeing as we only have 0.33% of the world’s population. It’s based on analysis from the 2008 Garnaut Climate Change Review. (If you want to venture into the weeds about what’s ‘fair’, there’s an excellent explanation here).
That means Australia can emit 10,400 Mt CO2-e between 2013-2050 if we want to do our 'fair share' to avoid 2°C warming.* To avoid 1.5°C, we must stay below 7760 Mt CO2-e.* Our current status (total emissions since 2013) is 5306 Mt CO2-e, according to the Greenhouse Gas Inventory. In the last financial year, Australia emitted 466.9 Mt CO2-e.
If that yearly pace continues, the 2050 budget would be exhausted in 2028 (for 1.5°C) and 2034 (for 2°C).
Too simplistic?
Carbon budgets have upsides and downsides.
As University of Melbourne researchers wrote, 'the key disadvantage of budgets is that they are often overdrawn. In the early days of a budget term, when the budget seems relatively generous, there is a natural bias towards spending rather than saving.'
What’s more, carbon budgets mask immense complexity at the risk of oversimplification. Carbon Brief has a detailed analysis here.
But on the plus-side, they highlight the inescapable rule that the more you spend now, the less you can spend later (assuming you intend to stay within your budget).
They also send a resounding message: time is short.
In 2021, the Climate Targets Panel gave Australia a reality check ahead of a global climate summit. They showed how emissions reduction targets should be derived from an emissions budget that strikes at the agreed target.
At the time, Australia’s emissions reduction targets were woefully inadequate
(26-28% by 2030). Today, the targets have levelled up (43%). Our actions are next.