Tim Osborn, do you know why the IPCC WGI glossary defines « pre-industrial » as it was before 1750? We found that global temperatures probably increased by more than 0.6 degrees Celsius between the pre-industrial period and the 1986-2005 period. This means that 2015 was at least 1oC warmer than in the pre-industrial era and was probably warmer by more than 1.1oC in 2016 (see Figure 2). Eli, I was not present during the Paris negotiations, so I`m not sure your statement that it was negotiated with the assumption that 1850-1900 – pre-industrial. Do you have the proof? B, for example, an explanation of the text or supporting documents? I was present at the plenary session, where the contribution of Working Group I to the IPCC AR5 was approved. There was certainly no agreement between all government delegates to the proposal to use 1850-1900 to represent the pre-industrial level and, as a result, the term pre-industrial level was replaced by the more accurate/direct 1850-1900, where it had been used. I was also called to the podium and asked for a scientific assessment of the global temperature difference between 1850-1900 and the pre-industrial industry — something I have not been able to do in the field, but the current work is trying to do. I have a stupid question, even though I`m not a climate scientist. Is there a simple value that I can use to adjust the base period for two generally available sets of temperatures like GISTEMP or NOAA GlobalTemp, so that I can adapt the respective base times to the pre-industrial baseline of your document? Thank you Rick H Part of the reason I ask this question is from a legal point of view, it would never fly. The Paris agreement was negotiated with an idea of what « pre-industrial » meant. Even if people decide that they prefer to say something « pre-industrial, » that wish does not change the terms of the agreement.
Trying to change the basic lines of an agreement after the agreement has been negotiated and ratified to force people to do things they have not accepted is not normal. I have to ask how do you justify changing the temperature baseline that is used after an agreement is negotiated? While I think the definition of the period « pre-industrial » and temperature/greenhouse gas/etc. Baselines is a good thing to do, it`s something that should have been done centuries ago.