How much air in the tank?

Scuba divers pay a lot of attention to the amount of air in their tank. Their lives depend on it.

In the same way, climate scientists are keeping a close eye on the amount of greenhouse gases in the atmosphere. Whereas scuba divers are concerned when their air supply runs low, scientists are concerned when the amount of greenhouse gases gets too high.

Scientists have calculated how much more CO2 we can add to the atmosphere and still stay within the limit of 2C warming. They calculate that the atmosphere can hold an additional 565 GT (gigatons) of CO2.  Two degrees centigrade is the target that world nations have agreed upon as a target. Scientists say this will give a 50% chance of avoiding the worst consequences of global warming.

Two degrees is not a get out of jail card, with 2C we have 100% chance of getting all the serious consequences of global warming (increased drought, heatwave, flooding, ocean acidification, storms and floods, and rising sea level) as well as a 50% chance of copping the very worst (massive loss of arable land, loss of coastal cities, mass species extinction, runaway global warming).

565 GT is the equivalent of about 15 GT a year between now and 2050. However, the IEA reports that the world emitted twice as much last year (31.6 GT in 2011) and the trend is rising. These figures give rise to two thoughts:

• At current emission levels, we will reach the 2C 'safety' target by 2030 and extreme weather events will have quadrupled.
• We need to halve our emissions right now and then reduce them to zero by 2050.

When a scuba diver's tank is running low, they don't ignore it ("Faulty dial, always lies"), or negotiate with it ("Come on, tank, give me another 30 minutes and I'll give you a shiny hologram sticker to make you look pretty.") or threaten it ("Give me more air or I'll kill your wife and children. I know where you live.")

It's the same with 565 GT. We can't ignore it or try to negotiate or threaten it. Yet this is exactly what the fossil fuel industry is doing. They are sitting on current known reserves of coal, oil and gas that would pump 2,795 GT carbon dioxide into the air if burnt. And they are busily looking for more - ExxonMobile spends $100 million every day on exploration for new reserves.

With a limit of 565 GT, the remaining 80% (2,230 GT) will be left in the ground as stranded assets unless carbon capture becomes economically viable.

The new Laggard to Leader report from Beyond Zero Emissions asks Australia to take the lead in recognising that 80% of the world's fossil fuel reserves cannot be used by putting a moratorium on new coal exploration and mining. Australia currently dominates world coal with 27% of all trade so our actions can have a big impact.

When Australia stops expanding its coal industry it will be like the scuba diver who recognises his tank is getting low and starts heading back to the surface.  At that point we'll be swimming hard, hoping we make it in time to avoid catastrophe.

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The Transformation tab reports examples of progress towards a low-carbon future. Here's the latest snippet. 

Saudi Arabia announced that it would install 41,000MW of solar over the next two decades (25,000 in solar thermal and 16,000 in utility-scale solar PV). The Saudis are not wasting time – there’s too  much money to be saved. The cost of the initiative is estimated at $100 billion, but it is estimated to save 523,000 barrels a day, or more than $19 billion a year at current oil export prices). This month the Saudis announced that the first of their solar auctions, totaling 2,000MW, will be held early in 2013. The second round of 2,500MW will be held in 2014. Source: Reneweconomy.