I thought some of you might be interested in this:
http://ec.europa.eu/dgs/energy_transport/figures/scenarios/doc/2006_scenarios_oil_gas_en.pdf It's a European Commission report on what happens over the next 30 years if oil prices keep going up, and gas either stays linked to the oil price or still goes up but slower.
I've only read the executive summary (the full pdf is 62 pages). It's a bit depressing: because coal prices rise slower than oil and gas (in both scenarios), coal use rises, which leads to increased CO2 emissions. In the medium gas price scenario this is offset by higher use of gas, renewables and nuclear, but when both gas and oil are expensive, the increase in renewable and nuclear energy is probably not enough to offset the coal emissions. Note these projections assume current energy policies; I'm not sure if that includes carbon-trading.