Environmental Engineering Reference
In-Depth Information
Fig. 3.2
Resource and
production ratio of various
resources. (NIMS
2007
)
Fig. 3.3
Comprehensive RPR of metal resources. (NIMS
2007
)
completely towards a new recycling-based society if our future is to be sustainable.
To provide an indicator of the scale of this challenge, Fig.
3.2
shows the reserve/
production ratio (RPR) of various metal resources and fossil fuels. It is seen from
the figure that the RPR of some important metals and fuels is less than 100 years.
From these results, a comprehensive average of RPR of metals can be calculated
and plotted against the year as shown in Fig.
3.3
. This value of RPR in 1980 was
120 years; however it decreased linearly and became less than 80 years in 2000.
If we extrapolate the value it suggests that the comprehensive RPR may fall to 10
years by 2040.
With such rapid changes taking place and predicted, it is important to have ap-
propriate indicators to allow us to assess the environmental burden in society, and
