Figure 7-5: Carbon in oil,
gas, and coal reserves and resources is compared with historic fossil-fuel carbon
emissions over the period 1860–1998, and with cumulative carbon emissions from
a range of SRES scenarios and TAR stabilization scenarios until the year 2100.
Data for current reserves and resources are shown in the lefthand columns.
Unconventional oil and gas includes tar sands, shale oil, other heavy oil, coal
bed methane, deep geopressured gas, gas in aquifers, etc. Gas hydrates (clathrates)
that amount to an estimated 12,000 Gt C are not shown. The scenario columns show
both SRES reference scenarios as well as scenarios that lead to stabilization
of CO2 concentrations at a range of levels. Note that if by the year
2100 cumulative emissions associated with SRES scenarios are equal to or smaller
than those for stabilization scenarios, this does not imply that these scenarios
equally lead to stabilization.