WGI AR5 Final Draft Now Online

  The final draft of the IPCC Working Group I 5th Assessment Report (WGI AR5) is now available online. It is still subject to editing and is expected to be published in January 2014. Chapter 2 Observations: Atmosphere and Surface has a subsection 2.4.1 Land-Surface Air Temperature which discusses the global average temperature change over several periods for the temperature anomaly record in Table 2.4. The periods near the end of the record indicate a higher rate of change.

  The damped random walk discussed in the last few posts of this blog have to be considered hypothetical at this time. It is debatable whether the fluctuations in the 5-year average are part of the natural variation in the temperature anomaly or part of the changes in the equilibrium temperature or both. This complicates the analysis of the record. If there is a damped random walk present then it would indicate that part of the changes observed in the 5-year average are inconsequential to long term climate change. It suggests that we may need to clarify what we mean by climate change by focusing on changes to the equilibrium temperature.