If Exxon made a net income of $41 billion last year (http://www.forbes.com/sites/christopherhelman/2012/04/16/whi...), then it's pretty much money for nothing.

BP's deepwater disaster indicates that not enough is being done to protect the environment, it hasn't stopped risky drilling. That should never happen again. Some of those profits could be turned over into environmental preventative protection. These companies smack of pure greed to me.

Exxon made a profit of $41bn on a turnover of $480bn - about an 8% profit margin. That's not really "money for nothing". That's a healthy return on a gargantuan investment.

Some tech stocks profit margins: AAPL: ~30%, MSFT: ~30%, GOOG: ~25%. 3-4 times higher than Exxon. Do those companies all make money for nothing too?

Exactly. You beat me to it. See source here, namely Tables 2 and 6: http://www.fas.org/sgp/crs/misc/R42364.pdf

Also here: http://ycharts.com/companies/XOM/profit_margin

Note that it was closer to 5% in Q2 2009.

But it would be much lower if these companies were held accountable for the massive environmental impacts that they have (beyond the direct impacts of a spill). Excluding things that are even "debatable" like climate change, pollution and the effects thereof are not. These socialized costs would make oil companies unprofitable.

I agree that oil companies benefit from externalities that aren't accounted for, but I'd really like to see a numerical demonstration that it would make them unprofitable - I'm totally unconvinced that oil demand is that elastic, and I think they'd be able to pass the increased costs on to customers.

Oil is more scarce and useful than money, it's hard to see what would make extraction unprofitable. A carbon tax would mostly disincentive wasteful consumers. I wonder if anything could prevent exploitation of shale gas with a really low EROEI.

Wouldn't another tax on fuel just hurt low-income consumers?

I'm not rich - I drive because I want/need to, not because it's cheap. Sometimes I drive for fun, to get out of town for a bit, and I don't have the most fuel efficient vehicle, so that could be considered wasteful. If gas cost $5,$6,$10/gallon where I live (Chicago) I would still drive. Someone working minimum wage, students, kids, and retirees, increased fuel cost could prevent them from driving altogether.

It will hurt some consumers if they change nothing, but cheap oil is not a right, and being dependent on it now or in the future should be discouraged for good reason (mostly because a lasting ecological catastrophe is worse than diminished standards of living). Some hints that will help commuters save money: better public transport, carpooling, working from home, moving out of suburbia.

Those things are all very much debatable. Unfortunately reasoned debate rarely occurs, what we get instead is hyper-partisan shouting matches.