Comments on: Roy Spencer presentation to the Heartland Institute conference http://www.carboncommentary.com/2008/03/28/81 A critical appraisal of issues in the move to a low-carbon economy Fri, 25 Jul 2008 13:02:06 +0000 http://wordpress.org/?v=2.3.3 By: Global Warming » Roy Spencer presentation to the Heartland Institute conference http://www.carboncommentary.com/2008/03/28/81#comment-468 Global Warming » Roy Spencer presentation to the Heartland Institute conference Mon, 07 Apr 2008 09:36:07 +0000 http://www.carboncommentary.com/2008/03/28/81#comment-468 [...] Chris Goodall wrote an interesting post today on Roy Spencer presentation to the Heartland Institute conferenceHere’s a quick excerptGlobal warming is usually thought to result in decreased low cloud cover, amplifying the effect of warming. Sir John Houghton’s standard undergraduate textbook on global warming says that ‘climate is very sensitive to possible changes … [...] […] Chris Goodall wrote an interesting post today on Roy Spencer presentation to the Heartland Institute conferenceHere’s a quick excerptGlobal warming is usually thought to result in decreased low cloud cover, amplifying the effect of warming. Sir John Houghton’s standard undergraduate textbook on global warming says that ‘climate is very sensitive to possible changes … […]

]]> By: Robert Palgrave http://www.carboncommentary.com/2008/03/28/81#comment-465 Robert Palgrave Tue, 01 Apr 2008 16:29:46 +0000 http://www.carboncommentary.com/2008/03/28/81#comment-465 Chris, Good to see such a topic raised on a serious website, and may you not be accused of heresy by doing so! A burning question a few years ago was whether the heat retaining effects of gases like CO2, CH4, N2O and CFCs were actually significant compared with the effects of water vapour. One source postulates that water vapour is responsible for 95% of the greenhouse effect, and that of the remaining 5%, 3.5% is due to CO2. Also that mankind's activity has nearly no impact on the levels of water vapour in the atmosphere. (www.geocraft.com/WVFossils/greenhouse_data.html). If the relative warming contributions of water vapour (95%) and CO2 (3.5%) are as suggested by this source, it means that doubling the CO2 concentration only increases overall atmospheric heat retention by about 3.5%. And increasing CO2 from 400ppmv (2008) to 450ppmv (2050 - if we're diligent) would increase the atmosphere's insulating effect by less than 0.5% (one eighth of 3.5%). Could such a tiny increase in the atmosphere's heat retention by itself lead to temperature rises of 2 degrees? Has the IPCC modelling included or excluded the greenhouse effects of water vapour? The simple analogy for all of this is to imagine a duvet where the quilt itself gives nearly all the insulation, and the cover provides a tiny fraction. The quilt represents atmospheric water vapour, the quilt cover is CO2. Putting a second cover on the duvet, ie doubling the CO2 is hardly likely to make you feel warmer in bed! I have never seen this water vapour question conclusively dismissed. IPCC view is that it is very likely that man's activities are the cause of increased (anthropogenic) greenhouse gases, and that in turn, these are very likely to be the cause of global warming. "Very likely" means there is a high level of certainty, but some room for uncertainty. It worries me that no-one seems to be allowed to explore the remaining uncertainty in an open and scientific way. Surely the precautionary principle would require that we devote a proportionate amount of time and effort looking for other explanations for global warming than the accepted wisdom? Otherwise we could do all this work to reduce emissions and stabilise the atmospheric concentrations of CO2 and CH4, and miss some other factor that is actually more significant in causing heating of the planet. What a shame if that turned out to be some other human activity that we could have modified? Chris,

Good to see such a topic raised on a serious website, and may you not be accused of heresy by doing so!

A burning question a few years ago was whether the heat retaining effects of gases like CO2, CH4, N2O and CFCs were actually significant compared with the effects of water vapour.

One source postulates that water vapour is responsible for 95% of the greenhouse effect, and that of the remaining 5%, 3.5% is due to CO2. Also that mankind’s activity has nearly no impact on the levels of water vapour in the atmosphere. (www.geocraft.com/WVFossils/greenhouse_data.html).

If the relative warming contributions of water vapour (95%) and CO2 (3.5%) are as suggested by this source, it means that doubling the CO2 concentration only increases overall atmospheric heat retention by about 3.5%. And increasing CO2 from 400ppmv (2008) to 450ppmv (2050 - if we’re diligent) would increase the atmosphere’s insulating effect by less than 0.5% (one eighth of 3.5%).

Could such a tiny increase in the atmosphere’s heat retention by itself lead to temperature rises of 2 degrees?

Has the IPCC modelling included or excluded the greenhouse effects of water vapour?

The simple analogy for all of this is to imagine a duvet where the quilt itself gives nearly all the insulation, and the cover provides a tiny fraction. The quilt represents atmospheric water vapour, the quilt cover is CO2. Putting a second cover on the duvet, ie doubling the CO2 is hardly likely to make you feel warmer in bed!

I have never seen this water vapour question conclusively dismissed.

IPCC view is that it is very likely that man’s activities are the cause of increased (anthropogenic) greenhouse gases, and that in turn, these are very likely to be the cause of global warming. “Very likely” means there is a high level of certainty, but some room for uncertainty. It worries me that no-one seems to be allowed to explore the remaining uncertainty in an open and scientific way. Surely the precautionary principle would require that we devote a proportionate amount of time and effort looking for other explanations for global warming than the accepted wisdom?

Otherwise we could do all this work to reduce emissions and stabilise the atmospheric concentrations of CO2 and CH4, and miss some other factor that is actually more significant in causing heating of the planet. What a shame if that turned out to be some other human activity that we could have modified?

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