On the contrary, Figure 1 is a conservative estimate of potential emissions from tar sands because: the
economically extractable amount grows with technology development and oil
price; the total tar sands resource is larger than the known resource, possibly much larger; extraction of tar sands oil uses conventional oil and gas, which will show up as additions to the purple
bars in Figure 1; development of tar sands will destroy overlying forest and prairie ecology, emitting biospheric CO2 to the atmosphere.