Written evidence submitted by Clive Best (IPC0053)

I am an independent scientist. I have a PhD in High Energy Physics and previously worked at CERN, Rutherford Lab, JET Fusion Experiment and the Joint Research Centre of the European Commission.  All opinions expressed here are entirely my own.

The fifth assessment report is a comprehensive and impressive review of the current status of climate science. Although the message remains one of warning, the results are actually rather encouraging. The relevant new conclusions of AR5 are:

1. The acknowledgement that up to half the observed warming since 1950 is due to natural effects.
2. That climate sensitivity estimates have now been reduced.  Manmade warming is likely to be less than 2C for a doubling of CO2 (560 ppm).
3. The current pause in warming may well continue until 2030 due to a natural 60-year cycle in ocean dynamics (AMO/PDO) – see figure 1. Thereafter we can expect another period of rapid warming.
4. All AR5 climate models overestimated warming till 2012 because they excluded this natural oscillation – see figure 2.
5. The risk of climate disruption and extreme weather impacts is very small.
6. Sea level rise is a modest 60cm by 2100. Sea defenses can easily cope with this.
7. There will always remain uncertainties in climate models due to the complexity of climate interactions.  As an example scientists still cannot model the dynamics of past glaciations nor predict when the next one will occur. Another ice age would be far more catastrophic than global warming.
8. The largest model uncertainties are clouds. Clouds play the same role as the white daisies do in Lovelock’s daisy world.

In general AR5 is good news for the world and good news for the UK.  The world has more time to adapt to a low carbon future than previously assumed.  Professor Dieter Helm makes a strong argument in  “The Carbon Crunch” for gas as a low carbon transition path. Other implications for UK energy policy are:

• Carbon targets can be relaxed. Investment in new wind generation too quickly is counter-productive as costs begin to outweigh benefits above 20% intrusion on the grid [1].
• More resources could then be invested in research and development on future technologies. For example:
• Energy storage
• Next generation solar, artificial photosynthesis
• Compact nuclear, thorium reactors
• Nuclear fusion, hybrid fusion/fission

References

1. A cost Benefit Analysis of Wind Power, Eleanor Denny, PhD. Thesis , 2007 University College Dublin.

Figure 1: A fit to the Hadley-CRU temperature anomaly data showing a strong 60 year cycle superimposed on an underlying logarithmic warming trend due to increasing CO2 levels.

Figure 2: Comparison of warming trends of CMPI5 models with the actual trend  measured by HADCRUT4. Taken from Box 9.1, Figure 2 AR5 WG1.

December 2013