Our Carbon Budget Is All But Spent, But Who In Canberra Is Counting?

Fairfax - Penny Sackett* | Will Steffen*

According to the ABC’s Vote Compass, a majority of voters has put the environment ahead of the economy as the top election issue. Yet the budget we haven’t heard about in this so-called "climate election" is the carbon budget. That’s the budget set by the laws of physics and chemistry to hold global warming to the safer side of 2 degrees.

A polar bear climbs out of the water in the Franklin Strait in the Canadian Arctic Archipelago. The Arctic is suffering dramatic loss of sea ice. Credit: AP

Barring some speculative technology deployed in the next decade on massive, unprecedented scales that pulls down more carbon from the atmosphere than we are putting up, the emissions budget that humans must not exceed is 1000 billion tonnes of carbon – give or take. That’s the total carbon budget – from the beginning of the industrial revolution – to keep global warming strictly below 2 degrees with at least a 2/3 chance.
But the amount we have left to “spend” is much less, for three reasons. First, humans have already emitted 585 billion tonnes of carbon over the course of history until the end of last year. That must be subtracted to see what’s left.
Second, other greenhouse gases, such as methane and nitrous oxide, also cause warming, so we need to account for their effects. That’s another 210 billion tonnes of carbon we can’t spend.
Finally, the budget must be reduced by 110 billion tonnes more, because warming increases the release of land carbon to the atmosphere, specifically through wildfires and the melting of permafrost, effects that reports from the Intergovernmental Panel on Climate Change have not taken into account.
fter doing the sums, only 95 billion of the original 1000 billion tonnes is left to spend on carbon dioxide emissions. With 10 billion tonnes of carbon emitted every year, without immediate action, humanity will burn through the remaining budget in just 10 years. At that point, the chances of holding warming to 2 degrees will drop below 2/3, and we might as well flip a coin to know whether the climate will exceed boundaries maintained for more than a million years.
To put that in an Australian context, we can divide that remaining 95 billion-tonne budget evenly across the world’s population. With 0.33% of the world’s population, Australia’s “fair share” of the remaining budget is 310 million (million, not billion) tonnes of carbon to “spend” on carbon dioxide emissions, which come primarily from burning fossil fuels.
Sound like a goodly amount? Well, using recent numbers from the National Greenhouse Gas Inventory, Australia would use up that “fair share” in just three years.
Three years. Now there’s something that fits into an electoral cycle. And that’s not even counting the carbon dioxide that results from exported Australian coal burnt overseas.
We are accelerating toward disaster. Carbon dioxide in the atmosphere continues to increase year after year. In fact, the rate at which it is increasing is itself increasing.
Renewable energy technologies, electric cars, improved land use, and managing waste are all important pieces of a transition to a healthy, prosperous Australia living within a carbon budget. But from a scientific point of view, the single most critical climate issue in this election is the elephant in the room.
You know the one, that rogue elephant that is trying desperately to remain invisible and not leave footprints on policy papers: the continued expansion of fossil fuel extraction in Australia.
Fossil fuel reserves already being exploited contain more than enough carbon to consume the remaining carbon budget for the 2 degrees Paris target. Simply put, it is senseless, dangerous and irresponsible to expand fossil fuel facilities in Australia (or anywhere else).
We are in the midst of a climate emergency that is disproportionately affecting the young, the poor, and the vulnerable. In emergencies, good leaders take considered, immediate and extraordinary action to combat the biggest source of threat. Australia needs leaders who acknowledge and commit to combating this climate elephant in the party room. Will they step forward before May 18?

*Penny Sackett, former Chief Scientist for Australia, is a physicist and honorary professor at the Climate Change Institute, Australian National University.
*Will Steffen is an emeritus professor at ANU and a councillor at the Climate Council. 

Links

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