NZCSC chairman Barry Brill has suggested to Environment Waikato that its Regional Policy Statement (RPS) should not be influenced by the climate change ‘Guidance Manuals’ (here and here) issued by the Ministry for the Environment in early 2008. Like the IPCC’s Fourth Assessment Report (4AR), their recommendations have been overtaken by recent scientific papers and data. His submission notes that modelled projections of 21st century warming rely upon two components – emission volumes and climate sensitivity. Here is his comment regarding future CO2-e tonnages – or, in other words, emission volumes.
1. The IPCC Report (2007)
In 1998, the IPCC commissioned consultants – economists, futurists, statisticians, demographers, etc. – to establish story-lines of how the world might develop over the following century. This group eventually brought out a detailed book, the “Special Report on Emissions Scenarios” (“SRES”) of 40 diverse story-lines, any of which might conceivably capture the emissions profile of the 21st century.
Trenberth says the IPCC itself has no view as to the correctness of the Scenarios: “They are intended to cover a range of possible self consistent “story lines” that then provide decision makers with information about which paths might be more desirable… There is no estimate, even probabilistically, as to the likelihood of any emissions scenario and no best guess.” Continue Reading →
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