23 September 2016

Why is emergency-scale action necessary?

The world now faces a climate emergency. Our scientists tell us. We know it. Slowly the political elite are realising that the current international climate policy-making paradigm is dying of failure. Recognition of the climate emergency is now written into the platform for the Democratic Party for the 2016 US presidential election.

So how does our scientific understanding guide as to constructing a new way of looking at the challenge, as to what is happening, what is safe, and how we should respond? The Victorian Climate Action Network held a workshop on these questions on 11 September 2016. The slides below were the contribution by David Spratt to the first session, which asked the question ‘Why is emergency-scale action necessary?’

09 September 2016

Unravelling the myth of a "carbon budget" for 1.5C

by David Spratt
  • The carbon budget concept carries several and significant uncertainties, many of which are not fully appreciated, and which limit the political usefulness of the method.
  • The published 1.5°C carbon budgets all have an unacceptably high risk — of a one-in-three or greater chance — of exceeding the target temperature. Scenarios with a 50% chance of not exceeding the 1.5°C target have a 33% chance of exceeding 2°C of warming, and a 10% chance of exceeding 3°C of warming.
  • All published 1.5°C emissions-reduction scenarios for this century involve significantly “overshooting” the target for several decades (up to 1.8°C of warming) before returning to the target figure by 2100. 
  • From a sensible risk-management viewpoint, there is no carbon budget available for the 1.5°C target. Thus, achieving 1.5°C in the medium term means drawing down every ton of carbon dioxide emitted from now on.
  • The damage that will eventually be caused by the current level of warming of 1°C is beyond adaptation for many nations and peoples. 1.5°C is not a safe target.