The actual reason I went to Bonn last week was to participate in a side event run by The Oxford Institute for Energy Studies. They put forward the view that the real issue at hand is not the emissions in 2020 or 2050 or any other year, but the total additional GHG carrying capacity of the atmosphere in relation to a temperature objective. The full story on this appears in the 30th April edition of Nature.
To limit temperature rise to 2 deg.C, the number is about one trillion tonnes of Carbon, or 3.67 trilllion tonnes of CO2 (equivalent). That number is even smaller for a low risk (of exceeding 2 deg.C) scenario. The problem is, we have already used up about half this space, so we have 1.8 trillion tonnes of space left. Given our current usage patterns, 1.8 trillion tonnes doesn’t go far. I did some quick calculations and came up with the following;
- Even without accounting for extra bio-CO2 being released into the atmosphere through landuse change or the impact of the non-CO2 gases, we have to be done with fossil fuels globally by about 2060. One interesting contributer to this which I assume for my calculation continues unabated through the whole century, is cement. The manufacturing process releases fossil carbon into the atmosphere as the calcium carbonate is processed. The cement industry is growing rapidly as developing country cities rise from the forests and plains. The result is that over the next hundred years that one industry uses up at least one hundred billion tonnes of the available space.
- By contrast, if we can apply carbon capture and storage (CCS) to all our coal use by 2050, oil and gas can continue to support our energy needs until the end of century (albeit declining from 2020), which approximates to the complete use of current proven reserves (as per the BP Statistical Review of World Energy) – and of course there is still the cement.
The point here is that looking at the total space available is very instructive. It will help guide the policy process and clarify thinking on energy use and the application of technologies such as CCS. It also makes us aware of the cummulative impact of all the other things we do.
But again, there is no reference to anything like this in the negotiating text. The Oxford team have set themselves the task of making this happen, although given all the competing interests in the negotiating process, it represents a formidable challenge. I hope they succeed.