There is a finite amount of fossil carbon sources on Earth.
According to the latest BP Statistical Review of World Energy published in June 2013[1] following proved reserves are accounted for in the whole World:

Oil	235.8	1012 Kg	corresponding to	16.7	1012 Kmol C
Oil sands	62.6	1012 Kg		4.4	1012 Kmol C
Coal	860.9	1012 Kg		71.7	1012 Kmol C
Gas	187.3	1012 m3		8.4	1012 Kmol C

In addition, frozen Methane clathrate is found on ocean floor and in permafrost. The estimate quantity is somewhere between 500 and 2500 Gigatons of carbon[2]. Assuming that the lower quantity will be exploitable, this will add a sizeable CO₂ emission potential:

Methane clathrate	500	1012 Kg C		41.7	1012 Kmol C
			Total	142.9	1012 Kmol C

 

What would be the atmospheric CO2 concentration?

During the Holocene and before the industrial era it is assumed that a CO₂ concentration of 280 ppm remained quite constant.

Since the beginning of the industrial era (1750) it is estimated that 365 billion metric tons of carbon have been emitted by human activities into the atmosphere[3].
From these 30.3·10¹² Kmol of CO₂ approx. 2/3 remained in the atmosphere to reach a concentration of 390-400 ppm and 1/3 was captured in the form of additional biomass or sediments.

If in the total atmosphere of 182’000·10¹² Kmol the same ratio would apply, burning all fossil reserves would add 525 ppm to the present level, and therefore the “ultimate” CO₂ concentration would reach 925 ppm.

What temperature increase could it provoke?

According to Myhre et al[4] the primary forcing resulting from a change of CO₂ concentration is:

   , expressed in [W m^-2 K^-1]

Using a simple two layer static model of the atmosphere[5] the corresponding temperature change would look as the following:

		Forcing primary	ΔT primary		Forcing feedback	ΔT feedback	ΔT overall
		[W m-2 K-1]	[K or °C]		[W m-2 K-1]	[K or °C]	[K or °C]
		(Myhre et al.)
Reaching 925 ppm from 280 as before industrial era		6.39	Surface	1.245	-1.62	-0.318	0.93
			TOA	2.275	-2.96	-1.075	1.20
Reaching 925 ppm from today’s 400		4.49	Surface	0.875	-1.14	-0.223	0.65
			TOA	1.603	-2.08	-0.756	0.85
TOA: “Top Of the Atmosphere”

Thus, without taking into account any feedback the temperature change since the beginning of the industrial era would be 1.25 to 2.28°C, and with a feedback of -1.3 W m^-2 K^-1 that combines the effects of Planck law, water vapour, clouds, albedo, and lapse rate[6], the overall anthropogenic temperature increase would be 0.93 to 1.20 °C, or it would increase by 0.65 to 0.85 °C from today’s level.

In view of the result is it worthwhile to worry?

Well, probably not. And then there will be nothing else left  to burn than renewable biomass!

The impact of about one degree on the temperature of the atmosphere may well remain hidden within wide variations due to other causes.

Therefore there is no urgency to adopt drastic controlling policies and it is wiser for us and many following generations to take the time to adapt to such uncertain and probably insignificant change.

It’s high time to do nothing rather than terrorizing the crowds with catastrophe scenarios.

Sorry for the activists, they will have to find another cause for saving the planet. They could begin with saving us from themselves by shutting up at once.

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