Saturday, December 05, 2015

Diamonds - and CO2 - are forever

Skeptical Science has addressed a related question,

Climate Myth...
It's waste heat
"Global warming is mostly due to heat production by human industry since the 1800s, from nuclear power and fossil fuels, better termed hydrocarbons, – coal, oil, natural gas. Greenhouse gases such as carbon dioxide (CO2 play a minor role even though they are widely claimed the cause." (Morton Skorodin)
Gordon Fulks has repeated assertions that CO2 doesn't matter. Here is his latest:
Unfortunately, proponents of Catastrophic Anthropogenic Global Warming continually sidestep all such tests, arguing as Diamond does, that CO2 is a greenhouse gas and adding more to the atmosphere has to warm the planet. That may be trivially true but numerically insignificant.
This last bit - "CO2 play a minor role even though they are widely claimed the cause" is a favorite "fulks-tale" that percolates through the nutosphere. Боже мой, it is good that real scientists call him out.

Being Onymous Guy, I felt I had to do my own calculation: I used data from controversial sources like NIST, NOAA, EIA, the usual rogue’s gallery.

The answer depends on the carbon source, but it boils down to this: within a year or so, regardless of source, the energy added to the planet through increased radiative forcings - the $25 term for the effects of global warming - exceed the enthalpy of combustion of that source.

The really bad news is that, once added the atmosphere, CO2 and its effects persist, not for millenia, but for hundreds of thousands of years, so the energy of combustion is extremely small compared to the lifetime accumulated radiative forcings from that added CO2.

As David Archer wrote,
The notion is pervasive in the popular and scientific literature that the lifetime of anthropogenic CO2 released to the atmosphere is some fuzzy number measured most conveniently in decades or centuries. The reality is that the CO2 from a gallon out of every tank of gas will continue to affect climate for tens and even hundreds of thousands of years into the future.
Source: Nature Climate Change

Supplement (thank Blogger for the Pretty Colors):

I used the data from sources below to find the specific enthalpy of combustion (averaging about 50 kJ/g C), and compare that to the specific planet-wide radiative forcing from CO2, currently about 1.15 mW/g C in CO2(g). The ratio of the specific enthalpy to the specific forcing is the time (in seconds) in which the enthalpy of combustion equals the accumulated energy due to CO2's radiative forcing, about 45 million seconds - 500 days or so.

Carbon Dioxide Emissions Coefficients (from the US Energy Information Agency)

(I) Miscellaneous conversion factors
Carbon content of CO2 1 BTU/J = 1055.056 J
Molar mass CO2 10^6 BTU = 1.055E+09 J
44.0095 1 kg CO2 = 272.9183472 g C
Atomic mass C so
12.011 1 kg CO2 / 1 M BTU =
mass fraction of carbon in CO2 2.587E-07 g C / J

Atmospheric Data
Quantity Value Units
Radiative forcing = α ln C/C0
CO2 (ppmv) 401.3 ppmv
α 5.35 W/m^2
C/C0 (C0=280 ppmv) 1.43321
Radiative forcing (W/m^2) 1.92557 W/m^2
Surface area of earth/m^2 5.1006E+14 m^2
Radiative forcing (W) 9.8216E+14 W
Seconds in a year 31556736 s/yr
Annual forcing (J) 3.0994E+22 J
Mass atmosphere / kg 5.1370E+18 kg
Mean molar mass/kg 0.02897 kg/mol
Mean moles in atmosphere 1.7732E+20 mol
Mean moles CO2 in atmosphere 7.1159E+16 mol CO2
Mean mass CO2 in atmosphere/g 3.1317E+18 g CO2
Mean mass C in atmosphere/g 8.5469E+17 g C
Radiative forcing per gram (W/g C) 1.1491E-03 W/g C

Fuel Time(yr)
Propane 1.69
Butane 1.64
Butane/Propane Mix 1.67
Home Heating and Diesel Fuel 1.46
Kerosene 1.47
Coal (All types) 1.12
Natural Gas 2.01
Gasoline 1.50
Residual Heating Fuel (Businesses only) 1.35
Jet Fuel 1.50
Aviation Gas 1.54
Flared natural gas 1.95
Petroleum coke 1.04
Other petroleum & miscellaneous 1.47
Asphalt and Road Oil 1.41
Lubricants 1.44
Petrochemical Feedstocks 1.50
Special Naphthas (solvents) 1.46
Waxes  1.47
Anthractie 1.03
Bituminous 1.14
Subbituminous 1.10
Lignite 1.09
Coke 0.93

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