Monday, 7 February 2011

Tipping Points and the top 1% OR “if you hope for 1° C don’t act for 4°C”

A week or so ago Prof Kevin Anderson, from Tyndall Manchester gave a talk to 4CMR entitled: Climate Change: Going Beyond Dangerous.  The talk assessed the numbers and the models used to determine policy on decarbonising the economy.  The consensus view, he argued, is as follows - an increased global mean temperature of 2°C (on pre-industrial levels) is the point at which climate change was considered a major problem, and the lowest stabilisation point that we could manage though practical and expedient policies. 

Assessing the latest research findings and analysing the data in great detail his conclusion was twofold:

2°C is likely to have dangerous (or extremely dangerous) consequences, and hence 1°C should be the upper limit if we are to avoid dangerous climate change (i.e. the consensus view is too optimistic: the target should be lower)

In practice, 2°C is becoming less likely, with 4°C a more likely stabilisation point if we implement even the more ambitious carbon emissions reduction strategies that are available to us AND assumes:

  • IPCC’s link between cumulative emissions and temperature is broadly correct
  • Non-Annex 1 nations peak emissions by 2025
  • There are rapid reductions in deforestation emissions
  • Food emissions halve from today’s values by 2050
  • No tipping points occur
His conclusion is that 2°C is nearly impossible and that 4°C is likely by 2070 and depending on the effects of various tipping points, there is a chance that stabilisation will be even higher (i.e. the consensus view is too optimistic: the target reduction is unobtainable).

The 2°C target is thus doubly pessimistic, but is there any room for optimism? Well, failure to reach a 1°C target assumes that policies and agreements are directed towards the global population, divided into countries and regions, which leads to the more profound question: If we are to meet a 1°C stabilisation point, how many people need to make the necessary changes to?