Hansen’s 1988 Testimony To Congress : Scenario A Is Business As Usual

5 Responses to Hansen’s 1988 Testimony To Congress : Scenario A Is Business As Usual

1. John Davis says:

   January 14, 2014 at 10:55 am

   I asked Gavin about this on RealClimate a few years ago. He was adamant that scenario B was closest to the actual forcings that have occurred. I can only assume his maths includes a huge reduction in growth of Methane or a swathe of those oh-so-malleable aerosols.

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   • stevengoddard says:

     January 14, 2014 at 1:28 pm

     If Gavin actually used radiative transfer models, he would know that doubling CH4 would have essentially no effect, and that CH4 is unstable and quickly breaks down in the atmosphere.

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   • Will Nitschke says:

     January 14, 2014 at 9:25 pm

     That was Hansen’s maths, not Gavin’s maths. Even though Gavin worked with Hansen from some of his commentary it’s not clear he understood Hansen’s model very well either. At least not in the sense that all his statements about it seem correct.

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2. darrylb says:

   January 14, 2014 at 9:12 pm

   Some facts RE Methane
   1: The concentration of CO2 in the atmosphere is about 235 times larger
   2. The half life of methane is about weven years (some of it lasts a little while, but the half life is relatively short
   3. Although the half life is short, farming, (swine and dairy in particular) is believed to account for 28% of emisssions of methane, (I have not verified those figures by anyone’s research)
   4. Methane is not saturated with respect to IR absorption and its internal oscillations result in the fact that its absorption spectra is much larger than CO2.
   5. Therefore because the rate of CH4 entering the atmosphere is arguably increasing, it should be a least a consideration, I do not have the facts regarding net concentrations.
   6. It is well known that water vapor followed by CO2 are the most significant greenhouse gases.

   Something that gets overlooked, Over the last 150 to 200 years the average temp of the atmosphere has increased by 0.6 to 1.0 deg C. That means that if the atmosphere is currently in equilibrium it would be emitting a little more heat now (The amount can be calculated)
   That also means that in order to increase in temp it would have to realize an increase in heat absorption. It may be that we have a slightly new equilibrium with an increase in gases.

   Conclusion: Methane should probably be considered as a minor player.

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3. darrylb says:

   January 14, 2014 at 9:13 pm

   Well in 2. seven years

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