Calculating the Effect$ of Trillion$ $pent to Control CO2: 00000.2 Degrees

From Wattsupwiththat, a letter from The Viscount Monckton of Brenchley to the Austrialian Prime Minister - Excerpt:

Let us pretend, solum ad argumentum, that a given proportionate increase in CO2 concentration causes the maximum warming imagined by the IPCC. The IPCC’s bureaucrats are careful not to derive a function that will convert changes in CO2 concentration directly to equilibrium changes in temperature. I shall do it for them.

We derive the necessary implicit function from the IPCC’s statement to the effect that equilibrium surface warming ΔT at CO2 doubling will be (3.26 ± ln 2) C°. Since the IPCC, in compliance with Beer’s Law, defines the radiative forcing effect of CO2 as logarithmic rather than linear, our implicit function can be derived at once. The coefficient is the predicted warming at CO2 doubling divided by the logarithm of 2, and the term (C/C₀) is the proportionate increase in CO2 concentration. Thus,

ΔT = (4.7 ± 1) ln(C/C₀)                           | Celsius degrees

We are looking at the IPCC’s maximum imagined warming rate, so we simply write –

ΔT = 5.7 ln(C/C₀)                                      | Celsius degrees

Armed with this function telling us the maximum equilibrium warming that the IPCC predicts from any given change in CO2 concentration, we can now determine, robustly, the maximum equilibrium warming that is likely to be forestalled by any proposed cut in the current upward path of CO2 emissions. Let me demonstrate.

By the end of this month, according to the Copenhagen Accord, all parties to the UN Framework Convention on Climate Change are due to report what cuts in emissions they will make by 2020. Broadly speaking, the Annex 1 parties, who will account for about half of global emissions over the period, will commit to reducing current emissions by 30% by 2020, or 15% on average in the decade between now and 2020.

Thus, if and only if every Annex 1 party to the Copenhagen Accord complies with its obligations to the full, today’s emissions will be reduced by around half of that 15%, namely 7.5%, compared with business as usual. If the trend of the past decade continues, with business as usual we shall add 2 ppmv/year, or 20 ppmv over the decade, to atmospheric CO2 concentration. Now, 7.5% of 20 ppmv is 1.5 ppmv.

We determine the warming forestalled over the coming decade by comparing the business-as-usual warming that would occur between now and 2020 if we made no cuts in CO2 emissions with the lesser warming that would follow full compliance with the Copenhagen Accord. Where today’s CO2 concentration is 388 ppmv –

Business as usual:                              ΔT = 5.7 ln(408.0/388) = 0.29  C°

–          Copenhagen Accord:           ΔT = 5.7 ln(406.5/388) =  0.27  C°

=          “Global warming” forestalled, 2010-2020: 0.02 C°

One-fiftieth of a Celsius degree of warming forestalled is all that complete, global compliance with the Copenhagen Accord for an entire decade would achieve. Yet the cost of achieving this result – an outcome so small that our instruments would not be able to measure it – would run into trillions of dollars.

and see the followup post here.