On Wednesday the second Structured Expert Dialogue of the 2013-2015 review began to assess overall progress towards achieving the long-term global goal, including the implementation of commitments under the Convention.
The IPCC authors conclude that there is a 1000 Gt carbon budget for humankind from the starting point of the fossil fuel era. Within that budget there is a 66% likelihood of staying below 2 degrees.
We have already used half of that budget and, taking into account other greenhouse gases, only 270 Gt can still be emitted to remain within the safe lines. That’s a shockingly small carbon budget to stay with a climate that is relatively safe – and even then substantial impacts will still occur.
Most numbers from the IPCC are associated with uncertainties. From a risk assessment perspective (or common sense, depending on how formal you want to be), higher uncertainty requires a lower carbon budget. So remember, even a 66% likelihood means a one-third chance of going beyond 2 degrees.
Furthermore, action on short-lived forcers like methane cannot replace or ‘buy time’ on long-lived greenhouse gases, especially CO2. We need substantial reductions of them all.
However, while the Structured Expert Dialogue did not formally draw conclusions, it is clear that the overall progress made so far towards achieving the long-term global goal is small and far less than what is necessary.
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