Torvalds Becomes an American Citizen
There's no insistence from the US to give up your previous citizenship when you become a US citizen. The State Dept even has a page about it:
This is really just a matter of practical policy ; it's impossible to police and some countries have no process for renouncing citizenship (others, such as Singapore, require you to give up your Singaporean citizenship if you ever take citizenship of another country). The only requirement the US has is that US citizens enter and leave the country on their US passport.
Report Blasts "Peak Oil" Theory
Tar sands and what not are all orders of magnitude more expensive
They're not, actually. Tar sand extraction becomes profitable above $40/barrel (Witness the boom currently occuring in Canada), and that's including capitalized R&D costs and infrastructure. Conventional extraction costs are, as I recall, around $18/barrel (again, including average cap costs, but that's going up now since most new field discoveries are deeper and/or smaller than before, requiring more expensive extraction processes).
Really, you might disagree with the report, but there's nothing insane or glaringly wrong with their position - and their projections for Chinese oil demands are actually pretty steep. And, I'll note, they don't actually factor in the substitution effects of what would happen if there's a sudden shift to auto fuel-cells or ethanol. You can bet that if, in 20 years time, H2 and ethanol are the major source of auto fuel in the US it'll have an impact on oil consumption.