Comments on: GCMs and Ice Ages

By: Computers Incapable of Modeling Climate: Billions Wasted To Perpetuate Deception

Computers Incapable of Modeling Climate: Billions Wasted To Perpetuate Deception — Tue, 03 Jan 2012 19:03:02 +0000

[...] confirms what Caspar Ammann told Steve McIntyre: GCMs (General Circulation Models) took about 1 day of machine time to cover 25 years. On this [...]

By: Steve Sadlov

Steve Sadlov — Fri, 25 Aug 2006 16:06:22 +0000

It would appear that one unique thing about the Holocene is indeed the success of Man as an organism capable of modifying the environment. On the one hand, we’ve mastered multiple processes for liberating carbon, and increasingly, managing, the carbon cycle. Some of it is via energy production and some of it is via cultivation and industrial processes. Balancing the liberation and management of carbon, however, are a number of other forcings, both intended and unintended, which also would need to be fully understood and accounted for in order to fully understand just what are the unique characteristics of the Holocene.

By: Steve McIntyre

Steve McIntyre — Fri, 25 Aug 2006 15:43:42 +0000

Transferred from Glacier Bay, Alaska

Re #46,

Muirgeo (and DanàÆàⶩ, the question of lead/lags in temperature/CO2 is an interesting one. In the pre-industrial period, it is quite clear that temperature leads the dance, and that CO2 follows temperature changes with some 600 years lag at the end of an ice age, and with several thousands of years at the start of a new ice age. The trend is 8-10 ppmv CO2 for each 1 C change. As there is a huge overlap (the transitions take many thousands of years), this allows climate modellers to include a huge feedback from CO2 on temperature, thus helping to increase (decrease) temperatures during transitions.

But there is one interesting exception in the Vostok ice core: the end of the previous interglacial, the Eemian. The temperature (and CH4 – methane) levels were already near their lowest, before CO2 levels started to decline. And the result of the ~40 ppmv reduction is not measurable in the temperature record. That points to a low influence of CO2 levels on temperature. See the graphs here.

Thus, while there is a quite good correlation between temperature and CO2 as cause and effect in the pre-industrial period (even during the Holocene: some 10 ppmv lower CO2 level during the LIA, thus caused by ~1 C difference, or 5 times more than MBH98/99 shows), it remains to be seen what the real influence of CO2 is on temperature…

Comment by Ferdinand Engelbeen “¢’¬? 25 August 2006 @ 3:34 am | Edit This
50.

If you want to find a relevant thread to muse about CO2 lead/lag times, find it. Otherwise no more in connection with Glacier BAy.

Comment by Steve McIntyre “¢’¬? 25 August 2006 @ 4:13 am | Edit This
51.

Steve,

The concern here is for inappropriate irrelevent posts…..my post have made every post on the Mann issue irrelevent and that’s what the support group is whining about.

Willis just asked me an incredibly good question on CO2 and temperature trends through the holocene…which I’ve been waiting for….. but I guess it’s inappropriate for me to give a response? If this is the new law then fine I’ll impose my own self ban…..There is nothing more to say until the MWP forest start showing from underneath receding glaciers. If you figure out a way for trolls like me to contribute I’ll see you then. Otherwise, the support group can carry on with statistical machinations on Mann’s paper and other “relevant issues”.

Willis….look at graph C for your answer. oops sorry..couldn’t help myself…. BYE BYE…gbalella/muirgeo troll signing off.

Comment by muirgeo “¢’¬? 25 August 2006 @ 9:12 am | Edit This

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By: Ian Castles

Ian Castles — Wed, 21 Dec 2005 11:31:34 +0000

Re #22. In response to your question (1), it has been my understanding that the IPCC B1 marker scenario (B1 IMAGE) stabilises atmospheric concentrations of CO2 at about twice the pre-industrial level (i.e., at around 550 ppm.) by around 2100, without any mitigation or Kyoto like actions. This is my lay interpretation of the fact that the modelled increases in CO2 burdens in the last four decades of the century are, successively, 16, 12, 8 and 4 ppm (see the relevant table in Appendix II of Climate Change 2001: The Scientific Basis). This apparent stabilisation in CO2 burdens is achieved notwithstanding projected increases in annual CO2 emissions of about 70 per cent in the first half of the century (see SRES, p. 506). The lowest IPCC emission scenario, in terms of the forcing pattern in 2100, is the B1T MESSAGE scenario. whioh according to Dr. Tom Wigley (speaking at the Expert Meeting I attended at the IPCC’s invitation in January 2003) yielded a burden of 475 ppm in 2100. I am subject to correction, but again it was my interpretation that under this scenario the CO2 burden would stanilise or fall below 475 ppm in the early 2100s. The Australian proposal was that the IPCC should examine a scenario in which growth in developing regions was less rapid than under the B1 scenarios (but still rapid by comparison with past experience). This isn’t “my” scenario, but in my view it’s a scenario that the IPCC should have explored.

I think that that answers your question (2). I don’t have a scenario that can be distinguished from the IPCC’s in observed CO2 fluxes and concentrations, other than that I believe it would be interesting to know what the B1T scenario would look like, if it were to be ajusted for more realistic levels of economic growth and power station construction in the early decades of the century.

Re your question (3), I don’t think economists, as economists, are equipped to answer the question whether there is climate change due to greenhouse concentration. I read the postings on this blog with interest, but the physics are beyond my ken. My expertise is in economic statistics. In that field, my position is mainstream: in fact, I’ve yet to meet a national accounts statistician or index number theorist who disagrees with the views that I’ve been putting on this matter for the past three years.

By: epica

epica — Wed, 21 Dec 2005 10:30:04 +0000

#17 and 18
thank you for your detailed answer. Sorry to bother you with more questions/precisions
1) You say stabilization is reached without any mitigation or Kyoto like actions. What is then the 2100 level for your scenario, when is (if ever) the 2*CO2 level reached?
2) If for example the next 20 years would be marked by a slow cooling trend to temperature levels of the 1940s that would be a clear indication that GW is not working like we (vast majority of climatologist) think. This is a rough statement without statistics. When would you say can your scenario be distinguished from the IPCC scenarios in observed CO2 fluxes and concentrations?
3) How would you characterize your position within the comunity of economist? Would you describe it as as marginal as a “there is no climate change due to greenhouse gas concentration” position among climate researchers or do you have the impression that your position is though only supported by a minority but at least a strong minority (in number and/or reputation)? Very subjective question, sorry.
Thanks again. I’ll check on the UN webside for population growth. In the article (not scientific but from a good journal) I have read that a fertility of 2.1 leads to the 9 billion stabilzation scenario, whereas 2.2 leads to 36 billion in 2300 and 2.0 to 2billion in 2300. Funny thing these exponential laws.

By: Willis Eschenbach

Willis Eschenbach — Wed, 21 Dec 2005 10:28:36 +0000

Ian, is there anyone we can write to in order to protest this economic travesty?

By: Ian Castles

Ian Castles — Wed, 21 Dec 2005 09:40:30 +0000

Yes Willis, I’ve been told that the Contributions of Working Groups II and III are unbelievably poor. As recently as 1999 the World Bank advised the UN Statistical Commission that “It must be clearly stated that … there is unanimous agreement among researchers and theoreticians; proper cross-country comparisons can only be made once values have been adjusted to eliminate differences in price levels using purchasing power parities.” To the best of my knowledge this is still the unanimous expert view, but this counts for little in the eyes of the IPCC milieu, including the Bank’s Chief Scientist, Robert Watson, the former Chair of the IPCC (he ceased to hold that position in April 2002, but his personal page on the World Bank’s website still says that he’s Chair). Dr. Watson hasn’t replied to my letter to him of 17 June in which I asked that he arrange for the Bank to present the scenarios of the IPCC, the Bank itself and the Millennium Ecosystem Assessment on a standardised basis. The IPCC milieu is determined to avoid having the SRES projections expressed in a way that would expose the fact that they are way out of line with the more professional work of bodies such as the US Energy Information Administration and the Paris-based International Energy Agency.

By: Willis Eschenbach

Willis Eschenbach — Wed, 21 Dec 2005 08:08:39 +0000

Re 17 & 18, oh, man, Ian, that’s bad, bad news. I assume that also means they’re going to use the discredited MER projections rather than the correct PPP projections?

Bummer …

By: Ian Castles

Ian Castles — Wed, 21 Dec 2005 03:54:59 +0000

In #17, I said that “electricity use in B1T MESSAGE in the developing countries between 2000 and 2030 is about twice as great as is estimated in the Reference Scenario of the International Energy Agency (IEA)”. I should have said “between 2020 and 2030″, i.e., the furthest-out decade in the IEA projection. The point of the calculation is to show that the short and medium-term projections of electricity growth by the IEA, which is well informed about national policies and about the programs of electricity supply authorities, are very much lower than the projections of the IPCC modellers (who were not at all well-informed about these matters).

By: Ian Castles

Ian Castles — Wed, 21 Dec 2005 03:45:39 +0000

Re #13. Thank you for your comments and your pertinent questions. Unfortunately there is no prospect of the IPCC scenarios being corrected to lower values, because the IPCC has declared that “the SRES scenarios provide a credible and sound set of projections, appropriate for use in the AR4.” As the SRES Summary for Policymakers had previously pronounced ex cathedra that the 40 SRES scenarios “are equally valid with no assigned probability of occurrence” (Figure SPM-1, p. 4), it appears that no further questioning of the SRES projections within the IPCC context will be permitted.

The UK House of Lords Committee expressed its concern that the Panel “had no intention of undertaking any significant reappraisal of the SRES for the IPCC Fourth Assessment Report exercise (AR4) for 2007″ and urged “a wholesale reappraisal of the emissions scenarios exercise.” The UK Government has responded with the claim that “IPCC’s emissions scenarios cover a very wide range and the most reasonable expectations about future outcome of global emissions in the absence of further mitigation action are likely to be included within the envelope.”

The projected level of cumulative emissions between 2000 and 2100 in the IPCC scenarios does indeed “cover a very wide range” – from 690 GtC (B1T MESSAGE) to 2455 GtC (A1C AIM) – but in my presentation to the IPCC Expert Meeting at Amsterdam in January 2003 and a more detailed paper prepared immediately after the meeting I gave eight reasons for believing that lower emissions levels than those in B1 MESSAGE could be projected “on the basis of assumptions that are fully defensible.” The Australian Government apparently agreed with one of my reasons, because in its submission to the IPCC on the scope and structure of the Fourth Assessment Report (March 2003), it argued that the scoping process “will need to … consider whether there are plausible emissions scenarios outside the range indicated in the SRES and if so, manage integration of such scenarios into the AR4 (for example, consider developing a further scenario with lower developing country growth than the B1 scenarios, but without the high population and slower rate of technology growth associated with the A2 and B2 scenarios)”. No such scenario has been produced.

In response to your question whether I can see signs that an effective reduction in emissions could be established before say 2050, I would answer with a qualified “Yes”. The peak level of emissions in the B1T scenario is reached in 2030. Like all of the SRES projections, this scenario does not include any future policies that address additional climate change initiatives such as implementation of the Kyoto Protocol. As noted in the previous paragraph, there are many reasons why the emissions profile assumed in B1T MESSAGE may be overstated. To take one example, the assumed increase in electricity use in B1T MESSAGE in the developing countries between 2000 and 2030 is about twice as great as is estimated in the Reference Scenario of the International Energy Agency (IEA) as published in World Energy Outlook 2002. The latter projections have been subjected to far more intense scrutiny than the IPCC projections and were used in the development of the estimates of investment requirements in the IEA’s World Energy Investment Outlook 2003. In the light of these considerations, it seems to me to be reasonable to believe that CO2 emissions could decline before 2050 in the absence of further mitigation action.

You are right that economic development in China and India is proceeding very strongly, but this is fully taken into account in many of the IPCC scenarios.

The projections of world population used in the A1 and B1 SRES scenarios reach a peak of about 9 billion in the middle of the century and decline to just over 7 billion by the end of the century. The UN Population Division has published high, medium and low projections of the population of the world and its major regions to 2300. These are available on the UNPD’s website.