The Exergy Evolution of Mineral Wealth - Thanatia: The Destiny of the Earth's Mineral Resources - page 413

2.5 x 10 6

14000

2072

12000

2

2017

10000

1.5

8000

6000

1

4000

0.5

2000

0

0

1900 1950 2000 2050 2100 2150 2200 2250

1900 1950 2000 2050 2100 2150

(a) Nickel sulphides (b) Potash

Fig. 13.42 The Hubbert Peak applied to nickel sulphides (a) and potash (b) reserves. Data

obtained from USGS (2010)

3500 1800

1600

3000

2082

1400

1986

2500

1200

2000

1000

800

1500

600

1000

400

500

200

0

0

1900 1920 1940 1960 1980 2000 2020 2040 2060 2080 2100

1900 1950 2000 2050 2100 2150 2200 2250 2300

(a) Tin (b) Titanium-ilmenite

Fig. 13.43 The Hubbert Peak applied to tin (a) and ilmenite world resources (b) . Data obtained
from USGS (2010)

38 and 20%, respectively. The exergy replacement costs between 1900 and 2009
(B ), i.e. the exergy of all depleted fossil fuels, was 414 Gtoe, which corresponds
to 46% of the world's total proven conventional fuel reserves in 2009 (898 Gtoe).
Fossil fuel exergy was consumed at an average degradation velocity (B ) of 4.8
Gtoe/yr. In the last decade, this velocity increased to more than 9 Gtoe/yr. From
the latter figure, it can be seen that oil contributes to 4.0, coal 2.9, and natural gas
2.4 Gtoe/yr.
If one adds the exergy loss of fossil fuels, to the exergy replacement costs of non-
fuel minerals, one discovers that Man has depleted, in the 20th century alone, a total
of 515 Gtoe, consumed at an average velocity of around 5.8 Gtoe/yr (by 2008 this
figure had increased to approximately 14 Gtoe). For the most part (80%) exergy
degradation is a consequence of the combustion of fossil fuels. The remainder is as
follows: potash for 7.6%, aluminium for 5.1%, iron ore for 4.8% and other minerals
for 2% (see Fig. 13.46).